DE102016212423A1 - Radiation detector and manufacture - Google Patents

Abstract

A radiation detector includes a substrate and a membrane and at least one spacer for holding the membrane spaced from the substrate, electrically contacting the membrane, and thermally insulating the membrane with respect to the substrate. In this case, the at least one spacer is subdivided into a first section and a second section in a direction between the substrate and the membrane, the length of which bridges less than a distance between substrate and membrane, the first and second sections being laterally offset from one another and laterally extending Element, such that the first and second portions are electrically connected in series across the laterally extending element, and wherein the laterally extending element contributes less than or equal to a thermal resistance of the at least one spacer as a sum of the thermal resistances of the first and second section. Alternatively, the at least one spacer may comprise an electrically and thermally conductive layer which extends in a section perpendicular to the substrate in a loop through the at least one spacer so that an electrical path through the at least one spacer over which the membrane is contacted, longer than one Distance between substrate and membrane is. Also alternatively, the radiation detector may include a substrate having a well and a membrane, wherein the well extends in the substrate in a direction away from the membrane, wherein at least one spacer for holding the membrane is spaced from the substrate, for electrically contacting the membrane and for thermal insulation of the membrane with respect to the substrate is formed, wherein the at least one spacer extends into the recess. Alternatively, or additionally, the spacer has sidewall roughness achieved by scallops to reduce phonon transport by surface scattering effects as well as by the resulting path lengthening. In addition, methods for producing such radiation detectors are presented.

Description

The present invention relates to a radiation detector and its manufacture, such. B. a bolometer and its manufacture.

Uncooled resistance microbolometer arrays, also referred to below as microbolometers, can be used to detect far-infrared radiation (8 μm-14 μm). These microbolometers are one possible realization of so-called infrared focal plane arrays (IRFPA).

Known microbolometers include a membrane which is suspended by two metal contacts by means of thin webs above the substrate in a vacuum and thus thermally insulated. Basically, the membrane consists of an absorber and a sensor layer. In order to ensure the lowest possible reflection of the incident infrared radiation, the layer resistance of the absorber layer is adapted to the characteristic impedance of air (approximately 377 ohms / sq). Furthermore, located below the membrane, a metal layer, which is referred to as a reflector, on the substrate. Light, in particular infrared light or far infrared light, which is incident on the bolometer, more precisely the absorber, is in part transmitted through the absorber and the sensor layer. By means of the metal layer or the reflector, the partially transmitted light or the transmitted radiation is reflected back and can then be absorbed by the upper absorber layer. The cavity between the absorber layer and the (lower) reflector forms an optical (Fabry-Perot) resonator. The distance between absorber layer and (Fabry-Perot) resonator is advantageously chosen such that the optical path (nd) is an odd multiple of one quarter of the main wavelength λ to be detected in order to satisfy the resonator condition (equation 1). The optical path is composed of the sum of the layer thicknesses weighted with the refractive indices of the media within the cavity (equation 2). nd = (2k + 1) λ / 4 (k = 0, 1, 2 ...) (equation 1) nd = Σn _i d _i (Eq. 2)

In a body with a temperature of z. B. 300 K would be the maximum of the spectral radiance at about λ = 10 microns. This results in an optical path of nd = 2.5 μm (k = 0). 1 outlines the basic structure of a microbolometer. This includes a substrate 2 and a membrane 3 which through metal contacts 17 at a distance d from the substrate 2 is spaced. The membrane 3 includes one of the substrate 2 facing sensor layer 3b and one to the substrate 2 opposite absorber layer 3c , The upper side of the substrate 2 has a metallization 2m which acts as a reflector for incident light.

Due to the absorption of the incident, especially infrared or far-infrared radiation, the thermally isolated membrane heats up 3 What a change in the electrical resistance of the sensor layer 3b entails. The temperature change of the membrane 3 is dependent on the thermal insulation by means of the webs or metal contacts 17 as well as the energy of the absorbed radiation and is usually several orders of magnitude smaller than the change of the radiator temperature. The change in resistance of the sensor layer 3b can then be determined using an integrated readout circuit (abbreviated to ROIC).

A key performance indicator for microbolometers is the Noise Equivalent Temperature Difference (NETD). This factor is defined as the temperature change of an object which generates a change of the measurement signal which corresponds to the noise of the system and thus is a measure of the sensitivity of the sensor (equation 3).

F is the f-number, A the absorber area, ε the emission coefficient, L the radiance and T the temperature of the object, u 2 / n the square of the total noise voltage, g _th the thermal conductance, and U _bias the bias voltage.

From Eq. 3, it can be seen that the NETD, inter alia, is significantly influenced by the thermal insulation of the membrane or the corresponding thermal conductance g _th . In general, the membrane is thermally poorly insulated from the substrate, since the suspension is done by metal contacts. The resulting thermal conductance in this case is not sufficiently small to achieve a good or satisfactory performance (NETD <100 mK), since the contacts are made via tubes with thick metal coatings. For reasons of process and stability, these metal coatings must be thick or have a minimum thickness and thus conduct the heat generated in the membrane relatively well.

In conventional, in 2 shown microbolometers is an improvement of the thermal insulation or reduction of the thermal conductance by additional connecting elements (webs 4s ) realized between the suspended membrane and the metal contacts k.

For example, Weiler teaches ( Weiler, Dirk, et al. "Improvements of a digital 25 μm pixel pitch uncooled amorphous silicon TEC-less VGA IRFPA with massively parallel sigma-delta ADC readout. "SPIE Defense, Security, and Sensing. International Society for Optics and Photonics, 2011 ) An array consisting of such microbolometers. A microbolometer contains an absorber, which is held by two webs, so that the absorber is in addition to the contact by the webs in a vacuum.

wobei λ_i die thermische Leitfähigkeit der einzelnen Stegmaterialien, b_Steg und d_Steg die Breite und Dicke der einzelnen Stegmaterialien und I_Steg die Länge der Stege ist. Der Faktor 2 ergibt sich, weil zwei Stege 4s vorhanden sind. Also sollte, um eine gute thermische Isolierung zu erzielen, die Querschnittsfläche der Stege 4s möglichst klein sein und die Stege 4s aus Materialien bestehen, welche eine geringe thermische Leitfähigkeit besitzen. Bezüglich der Wärmeisolierung ist der Anteil der Metallkontakte 4k meist gegenüber dem der Stege 4s zu vernachlässigen. Weiterhin wird die thermische Isolierung beeinflusst durch die Wärmestrahlung an die Umgebung. Da die Infrarotdetektoren jedoch im Vakuum betrieben werden, ist der Einfluss ebenfalls meist sehr gering, so dass insgesamt die thermische Leitfähigkeit der Stege 4s dominiert.Derthermal conductance of the webs g _webs can be determined by Eq. 4

where λ _{i is} the thermal conductivity of the individual web materials, b _web and d _web the width and thickness of the individual web materials and I _{bridge is} the length of the webs. The factor 2 results because two bars 4s available. So, to achieve good thermal insulation, the cross-sectional area of the lands should be 4s be as small as possible and the footbridges 4s consist of materials which have a low thermal conductivity. With regard to thermal insulation, the proportion of metal contacts 4k mostly opposite to the footbridges 4s to neglect. Furthermore, the thermal insulation is influenced by the heat radiation to the environment. However, since the infrared detectors are operated in a vacuum, the influence is also usually very low, so that overall the thermal conductivity of the webs 4s dominated.

The development of microbolometers is moving towards smaller and smaller pixel sizes for high-resolution IRFPAs. At the same time, the demands on performance increase. Currently, microbolometer arrays with a 17 μm pixel pitch are common. However, according to the invention, this should be reducible to a pixel pitch of approximately 12 μm. Scaling the pixel pitch from 17 μm to 12 μm halves the absorber area.

In general, a reduction in the pixel pitch due to the reduction of the absorber surface has a massive influence on the performance of the microbolometer.

The effective absorber surface is limited due to the required area for the realization of the webs. Depending on the design and structure of the webs or target value of the thermal conductance, the claimed area of the webs can be different in size. The absorber surface, however, has the same effect on the performance as the thermal conductance. If the pixel area is now reduced by a certain factor, theoretically the entire microbolometer could be scaled accordingly, so that the ratios of the individual areas (lands, contacts, absorber area) and distances to each other are always the same. The loss of performance would then u. a. determined by the scaling factor. However, this scaling with a fixed factor for all components is practically impossible, since such scaling limits the limits of lithography. Typically, a stepper lithography with a resolution of 0.35 μm is used for the production of microbolometer arrays. Often already in current but also in older Mikrobolometergenerationen (17 microns, 25 microns, 35 microns) feature sizes at the limit of this resolution is used, such. B. at the web widths and distances. Furthermore, the contact holes and upper contact surfaces can not be scaled arbitrarily small for process and stability reasons, so that a limit also exists here. In summary, the smaller the bolometers are, the land areas take up more and more space at a fixed thermal conductance relative to the pixel size. As a result, the effective absorber surface is additionally reduced and the performance is consequently greatly reduced.

In Li ( Li, Chuan, et al., Recent development of ultra small pixel uncooled focal plane arrays at DRS. Defense and Security Symposium. International Society for Optics and Photonics, 2007 ) will the Absorber layer spread over the entire pixel area umbrella-like. Such an arrangement is also called two-layer or Umbrella design, since the complete outer surface is available for the absorber. The disadvantage, however, is that the webs and the sensor layer continue to be in one plane. The thermal insulation is therefore limited by the free, available, pixel area. Furthermore, the resonator condition in the region of the suspension of the absorber is not met, which has a negative effect on the absorption.

Also in Niklaus ( Niklaus, Frank, Christian Vieider, and Henrik Jakobsen. MEMS-based uncooled infrared bolometer arrays: a review. Photonics Asia 2007. International Society for Optics and Photonics, 2007 ) Bolometers are discussed, one embodiment comprising a conventional bridge design and another an umbrella design similar to the design described in Li.

In the WO2016 / 005505 A2 There is a large area available for the absorber. According to the invention, however, the thermal conductivity should be further reduced. Thus, with a scaling of the pixel pitch, the desired performance of the microbolometer thus achieved should be achieved.

The approach of WO2016 / 005505 A2 Based on the realization of the thermal insulation and simultaneous electrical contacting of electromagnetic radiation detectors (especially infrared detectors) with the help of sufficiently long and thinly coated hollow tubes, which are also called nanotubes. These are in 3 shown in cross section and can be produced with technologies and processes from microsystems technology. The thermal conductivity of the contacts is compared to the webs, due to the thick metal coating so far very large and therefore does not contribute to the insulation. If, however, the outer walls of the round contacts are coated sufficiently thinly with a suitable metal layer, this results in a thermal conductance which is comparable to that of the webs or may even be significantly smaller. The thermal conductance of the contact tubes (see equation 5) (described here as nanotube contacts or nanotubes) can be determined analogously to Eq. Calculate 4, where circular rings form the respective cross-sectional areas. g = 2π / lΣλ _i (r 2 / i, 2-r 2 / i, 1) (equation 5)

The term r _{i, 2} -r _{i, 2} = d is equivalent to the thickness of the individual materials / layers within the contacts.

Similar to the lands, the spacers are long and made of thin materials which have low thermal conductivity. In addition, the basic radius r _{2.2 of} the contacts 4k also be chosen as small as possible. In other words, the total diameter D of the contacts, ie r _{N, 2} , should be as small as possible.

As described, the membrane supported by the spacers consists of a member which changes its electrical properties upon application of heat and an absorber layer. The temperature-sensitive element consists of either an electrical resistance, a capacitance, an inductance or a pn-junction (diode).

In addition to thermal insulation, the second function of the spacers is to electrically contact this element. In general, the nanotubes consist of an electrically conductive layer. In order to protect this conductive layer in the etching process of the sacrificial layer optionally further protective layers can also be deposited with the atomic layer coating. These protective layers must be electrically and thermally insulating and stable with respect to the etching medium of the sacrificial layer. The thicknesses of all layers of the nanotubes are in a range of 0.1 nm-1 μm.

The object of the invention is to provide a radiation detector and a manufacturing method, so that the manufacturability with the same electrical conductivity and high thermal isolation from the substrate or a better ratio between electrical and thermal conductivity of the membrane suspension can be achieved with a comparable manufacturing effort, or that of occupied space of the radiation detector with the same electrical conductivity and high thermal isolation from the substrate or vice versa, a better ratio between electrical and thermal conductivity of the membrane suspension at the same occupied space of the radiation detector can be achieved. Alternatively or additionally, the thermal resistance of the membrane suspension is to be increased or the thermal conductance be reduced by adjustments in the microstructure of the membrane suspension.

The object is achieved by a radiation detector according to one of the independent claims or according to a method for producing a radiation detector according to one of the independent claims.

Advantageous developments are in the dependent claims.

According to one aspect of the present invention, the manufacturability of the spacers is improved by dividing the spacer into two sections. As a result, the spacer can be extended in its maximum length between the membrane and the substrate. Usually, the maximum length of nanotubes - as a possible embodiment of spacers - for process reasons limited because z. B. only reliably to a limited depth, d. H. a limited length, can be deposited in openings to define, for example, spacer walls. Characterized in that a spacer is divided into two sections, both the first and the second section can be generated in the respective process engineering maximum realizable length. These are additionally connected via a laterally extending element. The latter could be used as an example to even further increase the thermal resistance.

In an advantageous development of this exemplary embodiment, a cross-section of an electrically conductive material of the first and second sections is less than or equal to 7 μm ² or less than or equal to 3 μm ² or less than or equal to 0.8 μm ² .

Advantageously, the distance between the laterally extending element and the membrane according to the resonator condition according to Eq. 1, whereby the element can serve as a back mirror by also being arranged laterally between the membrane and the substrate. This distance may for example be between 1 .mu.m and 2.5 .mu.m, while the distance of the element 5 to the substrate may be greater than 2.5 microns. Alternatively, the laterally extending element may be located more than 25% of the distance, advantageously more than 30% and more preferably more than 45% of both the substrate and the membrane. The laterally extending element may be arranged substantially centrally between the substrate and the membrane. This has the advantage that both the first portion and the second portion of the spacer can be formed in a maximum length, which is technically possible. In this case, the laterally extending element is not necessarily used as a rear-view mirror. The electrical path from the membrane to the substrate is thus maximized, thereby increasing the thermal resistance.

In an advantageous development, the laterally extending element is designed as a reflector for incident electromagnetic radiation, in particular light or infrared light. In this case, the reflective part of the laterally extending element must be formed below the membrane, so that light incident through the membrane is reflected back to the membrane. Thus, the light can be picked up again by the membrane, in particular the absorption layer of the membrane.

A radiation detector, as described in this first aspect of the invention and also the developments can be produced by the first and the second portion are respectively produced by means of ALD in openings of a first and / or second sacrificial layer. ALD allows thin metal layers. Through the sacrificial layers, a certain shape can be achieved or specified. The openings can be made by etching a hole in each of the first and second sacrificial layers. Advantageously, the etching is done by means of a DRIE process, wherein as a DRIE process in particular a Bosch and / or gyro process can be used.

• 1. Strukturierung einer ersten Opferschicht, sodass selbige ein Loch aufweist;
• 2. Aufbringen einer ersten Lage an leitfähigem Material in dem Loch und auf der ersten Opferschicht zur Erzeugung einer ersten leitfähigen Schicht;
• 3. Strukturierung der ersten Lage an leitfähigem Material, sodass selbiges in dem Loch einen ersten Abschnitt eines Abstandshalters und auf der ersten Opferschicht ein lateral verlaufendes Element bildet;
• 4. Erzeugen einer zweiten Opferschicht auf der ersten Opferschicht;
• 5. Strukturieren der zweite Opferschicht, sodass selbige ein Loch aufweist;
• 6. Aufbringen und Strukturieren einer zweiten Lage an leitfähigem Material, sodass selbiges in dem Loch in der zweiten Opferschicht einen zweiten Abschnitt eines Abstandshalters bildet, der über das lateral verlaufende Element mit dem ersten Abschnitt elektrisch in Reihe geschaltet ist;
• 7. Entfernen der ersten und zweiten Opferschicht.

Advantageously, a process to produce a radiation detector as described above may be accomplished in the following steps.

• 1. structuring a first sacrificial layer so that it has a hole;
• 2. depositing a first layer of conductive material in the hole and on the first sacrificial layer to form a first conductive layer;
• 3. structuring the first layer of conductive material such that it forms a first portion of a spacer in the hole and a laterally extending element on the first sacrificial layer;
• 4. creating a second sacrificial layer on the first sacrificial layer;
• 5. patterning the second sacrificial layer so that it has a hole;
• 6. applying and patterning a second layer of conductive material such that it forms in the hole in the second sacrificial layer a second portion of a spacer electrically connected in series with the first portion via the laterally extending element;
• 7. Remove the first and second sacrificial layers.

According to a second aspect, a radiation detector is improved with respect to the thermal insulation of the membrane from the substrate in that a spacer has an electrically and thermally conductive layer which extends in a cutting surface perpendicular to the substrate in a loop through the spacer. Thus, an electrical path through the at least one spacer, over which the membrane is advantageously electrically contacted to the substrate, is longer than a distance between the substrate and the membrane, which, for example, due to manufacturing limitations, as mentioned above, or for other reasons, such , B. the desire for a quarter wavelength distance between the membrane and a reflector is limited. Due to the loop-shaped configuration of the spacer or of the electrically and thermally conductive layer of the spacer, the electrical path and thus also the thermal path between membrane and substrate can be extended beyond the pure membrane / substrate distance. Thus, the thermal resistance increases with the same space, which is determined by the distance on the one hand and the lateral extent of the membrane and its suspension on the other. As explained in the Explanatory Notes to Equation 3, the thermal insulation (equivalent to a thermal resistance) of the membrane is a significant factor for the Noise Equivalent Temperature Difference (NETD). This defines the temperature change of an object, which generates a change of the measurement signal, which corresponds to the noise of the system. Thus, this is a measure of the sensitivity of the sensor. By extending the electrical and thus thermal path so an increased sensitivity of the sensor can be achieved.

Such at least one spacer for holding the membrane with an electrically and thermally conductive, loop-shaped layer passing through it can be produced by ALD and a sacrificial layer method, wherein a first and at least one second sacrificial layer can be deposited, with which the shape of the loop-shaped electrically and thermally conductive layer can be produced. It is therefore possible to specify a shape through sacrificial layers into which an electrically and thermally conductive, advantageously loop-shaped layer can then be deposited by means of ALD. In a further process step, the respective sacrificial layer or all sacrificial layers can then be removed by etching and advantageously the electrically and thermally conductive layer, the membrane and the substrate remain.

The at least one spacer may be formed in a preferred embodiment of the second embodiment of a series of laterally spaced columns. These are advantageously connected in pairs at their upper or lower ends. Upper or lower end means in this context, the end remote from the substrate or the substrate facing the end. At least two columns can be connected to each other via a laterally extending element at its lower end. A structure with two columns each, which are connected to each other via a respective laterally extending element at its lower end end, can be repeated, wherein the individual pairs of columns, which are connected to each other at its lower end by a laterally extending element, respectively their upper end can be connected to each other. Thus, an electrical path may form through a series of pairs of two pillars which are electrically connected in series. In this way, the electrical path can be extended and thus the thermal resistance can be increased almost arbitrarily.

The at least one spacer could also be formed as a column, in the wall of which the electrically and thermally conductive layer is arranged folded. In this development, a long electrical path can be achieved by the folded arrangement of the electrically and thermally conductive layer on the wall of the column very space-saving. Space saving in this context means that for the electrically and thermally conductive path forming the spacer, in a plan view (ie in the direction of the normal of the substrate) on the radiation detector little surface is needed to form the spacer. Due to the folded structure of the electrically and thermally conductive layer, the individual layers of the layers can be very close to each other. The individual layers may preferably be arranged so that the column which forms the spacer is composed of a plurality of coaxial, cylindrical layers located one inside the other. Since the individual layers can be electrically connected to each other at their ends of the cylinder, a very long electrical path can be achieved. The coaxial axis of the column is referred to as the axis of the radiation detector.

At least two different structures with a folded electrically and thermally conductive layer on the edge of the column are conceivable. In the first structure, the folded, electrically and thermally conductive layer may be disposed in the wall of the column so that the electric path can be formed in the sectional area on one side of the axis of the column. In this case, the cut surface already described, which is formed perpendicular to the substrate, is referred to as the cut surface. The cut surface can thus be clamped on at least one side by the normal of the substrate and the other side of the cut surface can be parallel to the surface of the substrate. This development has the advantage that the complete circumference of the column or of the electrically and thermally conductive layer which forms the column can be used for the electrical path. Thus, an electric current flowing from the membrane to the substrate may pass over the entire circumference of the pillar from the contact facing the membrane to the contact facing the substrate. The column can therefore be constructed symmetrically. Since the entire circumference of the wall of the column can be used for the electrically conductive path in this structure, the electrically and thermally conductive layer, which extends over a circumferential segment in a specific region of the electrically and thermally conductive layer, is damaged in sections. not to a failure of the electrical conductivity from one to the other end of the column. The electrically conductive path can still form over the remaining circumference of the wall of the column, so that the damage remains without influence on the electrical conductivity.

In an alternative structure of the development, in which the spacers are formed as a column, in the wall of which the electrically and thermally conductive layer may be folded, the electrically and thermally conductive layer in a cross section of the column (the cross section in plan view) may preferably form at least three rings. In this case, gaps between the preferably at least three rings belong to cavities, which are preferably both at an end facing away from the substrate advantageously at least partially open. This development has the advantage that the sacrificial layer, which can form the intermediate spaces between the at least three rings, can be well etched away. In particular, compared to the first structure, there may be a relatively large amount of space to introduce etching medium between the rings into the interstices. Thus, the sacrificial layer in the gaps can be removed reliably and quickly by etching, since the etching medium can easily and reliably reach the complete cavity in sufficient quantity. Why this is easier with this training, will be explained or apparent below.

In both structures, an occupancy of the inner walls of the column may be provided with a sacrificial layer during manufacture. The inner walls of the column can each be formed by individual layers of the electrically and thermally conductive layer. The sacrificial layer should be removed or removed before delivery or before release.

In the first structure, a single layer of the electrically and thermally conductive layer in the hole bottom may preferably be removed by ion etching. Thus, before the next layer of the electrically and thermally conductive layer is deposited, in the sectional area the connection in the pot-shaped hole bottom can be interrupted. This happens in particular in the second and the further, second layer of the electrically and thermally conductive layer in the hole bottom. Thus, upon completion of the radiation detector, etching medium may be introduced through the axis of the spacer between the upper and middle layers of the spacer to etch away the sacrificial layer located there. The distance through the axis of the multi-layer spacer is relatively wide. This makes it difficult to transport etching medium to the hole bottom and also to distribute it further in order to remove the complete sacrificial layer between the outer and middle layer of the electrically and thermally conductive layer.

For this reason, in the second structure, the symmetry can be broken. Compared to the first structure, etching medium can be introduced directly between the outer and the middle layer of the electrically and thermally conductive layer in order to etch away the sacrificial layer located there. Through an opening, which is attached to the end of the column facing away from the substrate, etching medium can easily be introduced into the outer of the two intermediate spaces, or etching medium can also be introduced into the inner space between the inner layer of the electrically and thermally conductive layer and the middle layer the electrically and thermally conductive layer, which was also covered in the manufacturing process with a sacrificial layer, are introduced. Thus, therefore, reliable, easy and fast etching medium can be introduced into the two spaces mentioned.

Furthermore, this geometry (with broken symmetry) also simplifies the final complete removal of the etching medium, so that the etching medium can not reach the environment during operation.

Both developments of the second aspect may be generated in a multi-stage sacrificial layer method in a manner similar to that above with respect to the first aspect.

In a further aspect, which in principle can also be combined with the previously enumerated embodiments, in the case of a radiation detector, a substrate is provided with a depression which extends on the membrane-facing side of the substrate in the substrate in a direction away from the membrane. The radiation detector comprises a spacer for holding the membrane, which extends into the recess in the substrate. An advantage of this aspect is that an additional path can be formed which extends at least partially into the substrate. At the same distance between substrate and membrane, the length of the spacer increases, which can thus form a greater thermal insulation. The electrical path from the membrane to electrically contact the substrate is maintained and the thermal resistance of the spacer increases. The substrate may include an integrated readout circuit having circuit elements thereof formed on a side of the substrate remote from the diaphragm. In this case, a metallization layer for contacting the circuit elements with one another may be arranged at a height between the membrane-facing side of the substrate and the bottom of the recess of the substrate. This can make the electrical connection between the circuit elements. In other words, the biden of the recess may be lower than one of the wiring planes of the substrate.

Thus, the distance between the contacting of the substrate, which is advantageously connected to the integrated readout circuit, to extend the distance of the recess in the substrate. Thus, without increasing the membrane / substrate spacing and thus increasing the volume trapped therewith, the thermal resistance of the spacer can be increased, thereby improving the sensitivity of the detector.

In an advantageous development, the side of the substrate facing the membrane can also be metallized at least on the surfaces which are located directly below the membrane. As a result, incident electromagnetic radiation, in particular light or infrared light, can be reflected back onto the membrane. Thus, with incident electromagnetic radiation, in particular light or infrared light, the temperature change of the absorber of the membrane increase. Advantageously, the metallization, which acts as a reflector, is substantially at the advantageous distance already explained (see equation 1).

In one aspect or a further development, which can be combined with all previously mentioned embodiments or developments, at least one spacer can be designed such that it has a wall roughness or wall waviness. This may have an amplitude (w) greater than 30 nm. As a result, phonon transport can be reduced by surface scattering effects and / or the resulting path lengthening. This can be achieved, for example, by scallops. The amplitude of the scallops can be greater than 30 nm. Scallops can be microscopic, arched structures. Due to this structure, the resulting thermal conductance can also be reduced by a resulting path extension of the spacers. The resulting path lengthening by the amplitude of the scallop bulge of the at least one spacer may be more than 5%, or 10% or 20%. The scallops or wall roughness and / or wall waviness can be generated by advantageously etching holes in a sacrificial layer for the deposition of spacers so that they have a wall roughness or wall waviness. Are now the walls of the holes metallized in the sacrificial or layers, z. B. when depositing the electrically and thermally conductive layer, so the said scallops form. These can reduce phonon transport through surface scattering effects. In principle, however, the phonon transport can also be achieved by structures or surface configurations other than scallops, provided that it is ensured that the shape or structure of the surface is lengthened and / or that phonon transport is reduced. The special structure of the holes can be achieved by z. B. in a Bosch process, the etching time of a single etching process is significantly increased. As in a chemical etching, such. B. in a Bosch process, the etching takes place in all directions, that is undirected, then forms the desired arcuate structure. Alternatively, for example, processes are also conceivable in which etching can first be carried out, for example, by ion etching in a single etching step to a certain depth in the direction of the normal of the hole or substrate to be etched, and then an omnidirectional, d. H. uniform etching in all directions can be made. In this way, by a mixture of ion etching and chemical etching, which happen alternately, the desired arcuate structure can be generated.

In an advantageous development, which can be combined with all embodiments, an etching protection layer can be deposited on the at least one spacer or the individual layers of the electrically and thermally conductive layer or the electrically and thermally conductive layer during the production of the radiation detector. By means of this etching protection layer, it can be achieved that the metallization is not damaged during ion etching and / or chemical etching, but only the first, second or third sacrificial layer is etched away.

Advantageously, the wall thickness of the electrically and thermally conductive layer of the at least one spacer is between 0.1 nm and 1 μm or between 1 nm and 0.5 μm or particularly advantageously between 10 nm and 100 nm.

The radiation detector may be a bolometer. In an advantageous embodiment, a plurality of radiation detectors can be combined to form an array, so that, as in the case of a CCD camera, an image which is composed of an array of pixels can be recorded. Of course, according to the invention, however, an infrared light image can be detected / recorded.

Preferred embodiments of the present invention will be explained in more detail below with reference to the drawings.

1 shows a schematic drawing of a conventional radiation detector in a sectional plane in which at least one side of the cutting plane is spanned by the normal of the substrate;

2 shows an SEM image of a conventional 25 microns pixel pitch microbolometer array with a contacting of the membrane via webs;

3 shows a schematic cross section in the horizontal of a nanotube contact consisting of two materials for contacting the membrane and a conventional spacer;

4a - 4d 12 show side sectional views of a radiation detector in various successive stages during the manufacture of a radiation detector according to an embodiment in which the spacer is divided into first and second sections;

5a - 5f 12 show side sectional views of a radiation detector at various successive stages during the manufacture of a radiation detector according to an embodiment, in which the spacer is formed from a series of pillars to form an electrical path extending in a loop in a sectional plane perpendicular to the substrate;

6a - 6g show a further development of 5 also in side-sectional views of a radiation detector at various successive stages during the manufacture of a radiation detector according to an alternative embodiment in which the spacer is formed from a series of pillars to form a looped electrical path in a sectional plane perpendicular to the substrate Diaphragm is at a height above the substrate that is less than a maximum extension of the spacer away from the substrate;

7a - 7y show side sectional views of a radiation detector in various successive stages during its manufacture according to an embodiment in which in the wall of the spacer, an electrically and thermally conductive layer, which forms the electrically conductive path, folded, here with a symmetrical structure;

8a - 8d 12 show side sectional views of a radiation detector at various successive stages during its manufacture according to an alternative embodiment in which an electrically and thermally conductive layer forming the electrically conductive path is arranged in the wall of the spacer, here with a structure which does not immediately follow the circumference of the spacer is to facilitate sacrificial material removal;

9a - 9e 12 show side sectional views of a radiation detector at various successive stages during its manufacture in which the electrical path between the membrane and the substrate is extended by the spacer, which is part of the electrical path, extending into a depression in the substrate;

10a - 10d Figure 4 shows side-sectional views of a radiation detector at various successive stages during its production wherein the thermal resistance of the spacer is increased by scallops which ensure an arcuate shape of the electrically and thermally conductive layer of the spacer to reduce phonon transport through surface scattering effects as well as resulting path lengthening.

1 shows construction of a conventional radiation detector, in particular infrared detector or bolometer. It explains basic ways of functioning. The conventional radiation detector 1 shows a substrate 2 which is a readout circuit 6 (Engl .: Read Out Integrated Circuit, short: ROIC) includes. From the substrate 2 is located at a distance d spaced a membrane 3 , The membrane 3 is through a metal contact 17 at the distance d from the substrate 2 held. On the substrate 2 is located in the direction of the membrane 3 So the membrane 3 facing side, a metallization 2m , which acts as a reflector for incident light or incident electromagnetic radiation. The membrane 3 consists of a sensor layer 3b which is the substrate 2 facing, and an absorber layer, which on the side facing away from the substrate of the membrane 3 located. The thermal insulation of the membrane 3 and thus the sensor layer 3b and the absorber layer passes substantially through the metal contacts 17 , Furthermore, the thermal insulation of the membrane can be further improved by webs 4s , which with the metal contacts 4k are connected. In 1 is shown by the radiation detector, a vertical section in the xz plane. A top view (in the xy plane) will appear in 2 shown. You can see the metal contacts 4k which of the two bridges 4s be contacted and so the metal contacts 4k with the membrane 3 connect electrically. It is obvious that the width of the webs 4s the thermal resistance from the membrane to the metal contacts 4k essentially determined (see equation 4). To determine the thermal resistance or the thermal conductance of the webs 4s g _webs flow the width b _web and the thickness d _web (ie the cross section of the web in the orthogonal direction to the flow direction of the stream) of the webs 4 a significant one. The bridges 4s consist essentially of metal, so that the specific conductance λ _i can not be significantly influenced.

A cross section through a nanotube, which in 3 is shown in the xy plane, and which for suspending the membrane or the spacing of the membrane 3 from the substrate 2 serves, was already in the WO 2016/005505 A2 described. The spacers 4 , take the thermal insulation of the membrane 3 from the substrate 2 with simultaneous electrical contacting of the electromagnetic radiation detectors. The spacers are as z. B. sufficiently long and thin coated hollow tubes (therefore called nanotubes) is formed. These can be produced using technologies and processes from microsystems technology. In this case, the thermal conductivity of the spacers (nanotubes) is very small compared to the webs due to the thicker metal coating of the webs and can thus contribute significantly to a thermal insulation. This is achieved by coating the walls of the spacers shown by way of example in this embodiment as being sufficiently thin with a metal layer, resulting in a very low thermal conductance. This can be according to Eq. 5 calculate. In 3 the radii r _1,1 , r _1,2 and r _{2 , 1} and r _2,2 are shown. However, spacers are also conceivable that consist of more than two layers. As in Eq. 5, the cross-section or the effective cross-sectional area of the individual layers (in FIG 3 represented in the xy direction) is essential for the thermal conductance of the entire spacer. Effective cross-sectional area is the contiguous area in cross section, which consists of a specific material.

However, in terms of process technology, limits are reached here which limit the effective cross-section of the spacers downwards, because at some point no stable nanotubes can be produced any more. The electrical path, which can form between the membrane and the substrate, but should have a lower thermal conductivity.

Embodiments are described below in which the spacer - also referred to as thermal via - improved by adapting the geometry or microscopic structure of the spacer in its thermal insulation and / or made easier to produce.

In the in 4a D illustrated embodiment of a radiation detector, which is also referred to as a multi-level nanotube bolometer. This is done by the spacer 4 along its length, ie along the direction between the membrane 3 and substrate 2 , is divided into sections, that is, with their respective length in the direction between membrane 3 and substrate 2 run. A laterally extending element 5 is located in the electrical path between the membrane 3 which preferably consists of an optional protective layer 3a and a sensor layer 3b composed, and a metallization 2m of the substrate 2 , The lateral element 5 sits between the first section 4a and the second section 4b of the spacer 4 , The first and second sections 4a . 4b of the spacer 4 are laterally offset from each other and across the laterally extending element 5 connected with each other. Thus, the first and second sections are 4a . 4b and the laterally extending element 5 electrically, but also thermally connected in series. This can be the substrate 2 opposite end of the second section 4b electrically via a second layer 25 an electrically and thermally conductive layer with the membrane 3 be electrically connected, so a location 25 , which is located in the membrane plane and may be formed, for example, as a further web, in addition to the laterally extending element, or as a frame around the actual membrane. The first paragraph 4a of the spacer 4 can be electrically connected to the metallization 2m of the substrate 2 get connected. In terms of process technology, such a radiation detector 1 be prepared in a multi-stage sacrificial layer method (s. 4a -D), which includes, for example, the following steps or stages.

• a) In einem ersten Prozessschritt kann dann eine erste Opferschicht 9 das Substrat 2 (bzw. den ROIC 6, insbesondere auf die Metallisierung 2m des Substrats 2) aufgebracht werden.
• b) In einem zweiten Prozessschritt wird die Opferschicht 9 strukturiert. In dem Beispiel von 4b ist gezeigt, dass ein Loch 7 in die erste Opferschicht 9 geätzt wird. Dies kann vorzugsweise durch ein DRIE-(z. B. ein Bosch- oder Gyro-)Verfahren geschehen. Alternativ ist auch Ionenätzen denkbar, um möglichst in Richtung der Normalen, d. h. in z-Richtung des Substrats 2, ätzen zu können. Dabei kann das Ätzen in Richtung der Normalen bzw. der z-Richtung automatisch durch die Metallisierung 2m des Substrats 2 beendet werden. Danach wird eine erste Lage 15 eines elektrisch leitfähigen Materials auf die erste Opferschicht 9 und in das Loch 7 abgeschieden. Dazu wird beispielsweise Atomlagenabscheidung bzw. ALD oder alternativ andere Verfahren, wie z. B. CVD, verwendet. Anschließend kann die erste Lage 15 der elektrisch und thermisch leitfähigen Schicht strukturiert werden, so dass sich das lateral verlaufende Element auf der Oberfläche der ersten Opferschicht 9 ausbildet bzw. verbleibt sowie das in dem Loch 7 verbleibende elektrisch leitfähige Material einen ersten Abschnitt des später vollendeten Abstandshalters 4 bildet.
• c) Eine zweite Opferschicht 10 wird dann aufgebracht, also z. B. auf die komplette Struktur bzw. ganzflächig abgeschieden. Anschließend kann die Membran 3, welche sich aus der optionalen Schutzschicht 3a und der Sensorschicht 3b, wie z. B. Halbleitermaterial, zusammensetzt, auf die zweite Opferschicht 10 abgeschieden und strukturiert werden. Entweder vor oder nach dem Abscheiden der Membran 3 kann ein weiteres Loch 7b in die Opferschicht 10 geätzt oder anders strukturiert werden. Der Strukturierungsvorgang kann in z-Richtung nach unten in Richtung des Substrats 2 durch das lateral verlaufende Element 5 limitiert werden bzw. das Material des letzteren als Ätzstopp verwenden.
• d) Als folgender Prozessschritt wird eine zweite Lage 25 elektrisch leitfähigen Materials aufgebracht (beispielsweise mittels ALD abgeschieden). Dies geschieht z. B. ganzflächig, um in dem Loch 7b einen weiteren Abschnitt des Abstandshalters 4 zu bilden, sowie einen lateralen Abschnitt 25 auf der Höhe der Membran 3, der den besagten Abschnitt mit der Sensorschicht der Membran 3 verbindet, zu bilden. Es bildet sich demnach ein sogenanntes Nanotube in dem Loch 7b in der zweiten Opferschicht 10, der den zweiten Abschnitt 4b des Abstandshalters 4 bildet. Anschließend wird das aufgebrachte bzw. abgeschiedene elektrisch leitfähige Material strukturiert. Dies kann geschehen, indem ein (schmaler) Pfad an elektrisch und thermisch leitfähigem Material zwischen der Membran 3 und dem zweiten Abschnitt 4b des Abstandshalters 4 auf der bisher erzeugten Anordnung übrig gelassen wird.

Starting point can be in a substrate 2 exist on which there is a metallization 2m as it is in 4a is shown.

• a) In a first process step then a first sacrificial layer 9 the substrate 2 (or the ROIC 6 , in particular on the metallization 2m of the substrate 2 ) are applied.
• b) In a second process step, the sacrificial layer 9 structured. In the example of 4b is shown a hole 7 into the first sacrificial layer 9 is etched. This may preferably be done by a DRIE (eg, a Bosch or Gyro) method. Alternatively, ion etching is also conceivable in the direction of the normal, ie in the z-direction of the substrate 2 to be able to etch. In this case, the etching in the direction of the normal or the z-direction automatically by the metallization 2m of the substrate 2 to be ended. After that, a first location 15 an electrically conductive material on the first sacrificial layer 9 and in the hole 7 deposited. For this purpose, for example, atomic layer deposition or ALD or alternatively other methods, such. B. CVD used. Subsequently, the first layer 15 the electrically and thermally conductive layer are patterned, so that the laterally extending element on the surface of the first sacrificial layer 9 forms or remains as well as in the hole 7 remaining electrically conductive material a first portion of the later completed spacer 4 forms.
• c) A second sacrificial layer 10 is then applied, so z. B. on the entire structure or over the entire surface deposited. Subsequently, the membrane 3 resulting from the optional protective layer 3a and the sensor layer 3b , such as B. semiconductor material, composed on the second sacrificial layer 10 be deposited and structured. Either before or after the membrane has been deposited 3 can another hole 7b into the sacrificial layer 10 etched or otherwise structured. The structuring process can be down in the z direction in the direction of the substrate 2 through the laterally extending element 5 be limited or use the material of the latter as an etch stop.
• d) The following process step becomes a second layer 25 electrically conductive material deposited (for example, deposited by ALD). This happens z. B. over the entire surface, in the hole 7b another section of the spacer 4 to form, as well as a lateral section 25 at the height of the membrane 3 comprising the said portion with the sensor layer of the membrane 3 connects to form. Accordingly, a so-called nanotube forms in the hole 7b in the second sacrificial layer 10 that the second section 4b of the spacer 4 forms. Subsequently, the applied or deposited electrically conductive material is structured. This can be done by placing a (narrow) path of electrically and thermally conductive material between the membrane 3 and the second section 4b of the spacer 4 left on the previously generated arrangement.

The particular advantage of this method is the following. In practice, the etching depth in the Bosch process is limited to a sacrificial layer, since a Bosch process has an etching angle and thus the diameter of the hole bottom 7 becomes narrower with increasing etching depth. This impairs or limits the mechanical stability of the manufactured nanotubes. By the spacer 4 into a first and a second section 4a . 4b but can be a spacer 4 can be achieved, which has a longer effective (nanotube) length as actually appearing possible due to the process conditions. In addition, the electrical resistance through the laterally extending element 5 be enlarged. In this case, the contacts of the laterally extending element 5 with the first section 4a or second section 4b at opposite ends of the laterally extending element 5 are located. Thus, a long path can be achieved, which further reduces the thermal conductance.

It was accordingly according 4 a radiation detector with a substrate 2 and a membrane 3 described that at least one spacer 4 for a) holding the membrane 3 spaced from the substrate 2 , b) electrical contacting of the membrane 3 with, for example, a contact or connection or even an evaluation circuit on or in the substrate and for c) thermal insulation of the membrane 3 with respect to the substrate 2 having. In one direction between substrate 2 and membrane 3 , ie in the vertical direction in the figures, is the at least one spacer 4 in a first section 4a and a second section 4b articulated, whose length is less than a distance between each substrate 2 and membrane 3 bridged. In the example shown, there were two, but of course there may be more. The first and second sections 4a . 4b are laterally offset from one another and via a laterally extending element 5 are connected. The first and the second section 4a . 4b are over the laterally extending element 5 electrically connected in series, ie, extending therebetween, connecting, for example, the upper end of one section to the lower (substrate facing) end of the other section. The lateral element 5 contributes less or equal to a thermal resistance of the at least one spacer 4 as a sum of the thermal resistances of the first and second sections 4a . 4b That is, the spacer sections are each of the type as already described above, which are designed not only to allow the electrical conduction between the membrane and substrate, but also to reduce the thermal conduction as possible. A cross section of electrically conductive material 8th of the first and second sections ( 4a . 4b ) Is for example equal to or less than 7 microns ² or less than or equal to 3 microns ² or smaller or equal than 0.8 micron ² is selected to achieve an appropriate thermal resistance behavior, but other values are of course also conceivable. The lateral element 5 is, for example, centered or the membrane-to-substrate distance is divided evenly among the sections, so that in the case of two sections the element 5 essentially midway between substrate 2 and membrane 3 is arranged. It is also possible that the element 5 for example, more than 25% of the distance, or more than 30% of the distance, or more than 45% of the distance from both the substrate 2 as well as the membrane 3 is arranged remotely. Although not shown, it is possible for the laterally extending element 5 as a reflector 5a is designed for incident electromagnetic radiation and for this purpose between, namely both in the layer thickness direction and seen laterally, the membrane and the substrate extends.

In 5 another embodiment is shown. In this case, the thermal conductance can be reduced by a laterally extending element 5 between a first and a second sacrificial layer 9 . 10 used in the process to make a turn of the spacer 4 to reach. A possible process with the example, individual process steps for generating such a radiation detector in a so-called vertical meander nanotube execution may include the process steps a) to f) (as in 5a - 5f ). First, the radiation detector in the final product (but before the preferably complete etching away of the sacrificial layers 9 . 10 ), as in 5f shown. On the metallization 2m a substrate 2 can become a first sacrificial layer 9 over which there is a second sacrificial layer 10 can be located. On the second sacrificial layer 10 can a membrane 3 which are made up of an optional protective layer 3a and a sensor layer 3b can assemble. The membrane 3 , in particular its sensor layer 3b , can handle a second layer 25 an electrically and thermally conductive layer are contacted. In this case, the electrical contact between the membrane 3 and the metallization 2m are made by a continuous spacer section 14d , hereinafter also referred to as pillar, which (or which) through the first sacrificial layer 9 and the second sacrificial layer 10 up to the metallization 2m can penetrate. Between the continuous spacer section 14d which extends from the top of the second sacrificial layer 10 up to the metallization 2m of the substrate 2 extends, and the membrane 3 are in the electrical path from the membrane 3 further spacer sections or columns 14z arranged. However, these extend only through the second sacrificial layer 10 to a laterally extending element 5 , In this case, a spacer section extends in the electrical flow direction 14z from the top of the second sacrificial layer 10 to the laterally extending element 5 and another spacer 14z from the laterally extending element 5 to the top of the second sacrificial layer 10 , Here is the electrical contact between the two mentioned spacers 14z at the top of the second sacrificial layer 10 interrupted. The electrical connection or the electrical path of the spacer takes place only via the laterally extending element 5 between the sacrificial layers at a height between the membrane and the substrate. An end of a structure just described, consisting of two spacer sections 14z and a lateral element 5 is with the membrane 3 connected and the other end with the continuous spacer section 14d which extends from the top of the second sacrificial layer 10 up to the metallization 2m extends. As in 5 As can be seen, any number of such paired structures just described could be strung together so that the electrical and thus thermal path lengthened. The individual structures consisting of two spacer sections 14z and a lateral element 5 can be connected to each other at the top. So there can be a series circuit. Thus, an electrical path from the membrane 3 to the continuous spacer section 14d form, which directly with the metallization 2m connected is. The electrical path should be long and, if possible, through all of the structures described, each one extending laterally 5 and two spacer sections 14z include, a radiation detector 1 walk.

• a) Wenn noch nicht vorhanden, Aufbringen einer Metallisierung 2m auf das Substrat 2. Anschließend Aufbringen einer ersten Opferschicht 9 und Aufbringen einer ersten Lage 15 einer elektrisch und thermisch leitfähigen Schicht 8 auf die erste Opferschicht 9. Die elektrisch und thermisch leitfähige Schicht 8 kann aus Metall sein. Dabei kann das Aufbringen der ersten Opferschicht 9 durch Abscheiden (z. B. durch CVD oder ähnliche Verfahren) geschehen. Das Aufbringen der ersten Lage 15 kann durch Abscheiden, insbesondere durch ALD, geschehen.
• b) Strukturierung der ersten Lage 15 der elektrisch und thermisch leitfähigen Schicht 8. Aus dieser ersten Lage 15 kann das mindestens eine lateral verlaufende Element 5 gebildet werden. Dieses wiederum kann eine untere Kehre für den vertikalen Mäander bilden. Der vertikale Mäander bzw. viele aneinandergereihte vertikale Mäander bilden dabei den Abstandshalter 4.
• c) Aufbringen (beispielsweise durch Abscheiden) der zweiten Opferschicht 10 sowie Aufbringen (beispielsweise durch Abscheiden) und Strukturieren der Membran 3. Diese kann eine optionale Schutz- und Sensorschicht 3a, 3b aufweisen. Die Sensorschicht 3b kann aus einem Halbleitermaterial bestehen.
• d) Anbringen (beispielsweise durch Ätzen) von Löchern 7. Dies kann beispielsweise mittels des Bosch- oder Gyro-Prozesses geschehen. Die Wände der Löcher 7 können später beschichtet werden. Dies kann beispielsweise durch Atomalgenabscheidung (ALD) geschehen. Dabei kann ein Loch 7 durch die erste und zweite Opferschicht 9, 10 geätzt werden bis zur Metallisierung 2m des Substrats 2 und jeweils zwei Löcher 7, welche jeweils ein lateral verlaufendes Element 5 terminiert werden.
• e) Abscheidung einer zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8, vorzugsweise mittels ALD. Diese kann dazu dienen die Membran 3 elektrisch mit der Metallisierung 2m des Substrats 2 zu verbinden.
• f) Strukturierung der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8. Hierdurch kann sich ein mäanderförmiger Pfad über die Abstandshalterabschnitte 14z und das lateral verlaufenden Element bzw. die lateral verlaufenden Elemente 5 bilden. Dieser ist vorzugsweise möglichst lang. Dabei kann ein elektrischer Pfad von der Membran 3 durch die beschriebenen Strukturen aufweisend jeweils ein lateral verlaufendes Element 5 und zwei Abstandshalter 14 gehen. Die zwei Abstandshalter 14z werden nach unten in Richtung des Substrats 2 durch das lateral verlaufende Element 5 beendet. Dadurch sind die beschriebenen Strukturen elektrisch in Reihe schaltbar bis zu demjenigen (durchgehenden) Abstandshalter 14d, welcher sich von der Oberseite der zweiten Opferschicht 10 bis zur Metallisierung 2m erstreckt. Durch diesen durchgehenden Abstandhalter 14d wird also eine elektrische Verbindung zur Metallisierung 2m erreicht werden. Die beschriebenen Strukturen können sich von der Membran 3 gesehen aus mäanderförmig von der Oberseite der zweiten Opferschicht 10 in Richtung der Grenze zwischen der ersten und zweiten Opferschicht 9, 10 ausbilden. Insgesamt kann so ein schleifenförmiger elektrischer Pfad bis zur Metallisierung 2m erreicht werden.

In terms of process, such a structure can be produced as follows:

• a) If not present, apply a metallization 2m on the substrate 2. Then applying a first sacrificial layer 9 and applying a first layer 15 an electrically and thermally conductive layer 8th on the first sacrificial layer 9 , The electrically and thermally conductive layer 8th can be made of metal. In this case, the application of the first sacrificial layer 9 by deposition (eg by CVD or similar methods). Applying the first layer 15 can be done by deposition, in particular by ALD.
• b) Structuring the first layer 15 the electrically and thermally conductive layer 8th , From this first location 15 this can be at least one laterally extending element 5 be formed. This in turn can form a lower turn for the vertical meander. The vertical meander or many juxtaposed vertical meanders form the spacer 4 ,
• c) applying (for example by deposition) the second sacrificial layer 10 and applying (for example by deposition) and structuring the membrane 3 , This can be an optional protection and sensor layer 3a . 3b exhibit. The sensor layer 3b may consist of a semiconductor material.
• d) attaching (for example by etching) holes 7 , This can be done for example by means of the Bosch or Gyro process. The walls of the holes 7 can be coated later. This can be done for example by atomic deposition (ALD). This can be a hole 7 through the first and second sacrificial layers 9 . 10 etched to metallization 2m of the substrate 2 and two holes each 7 , which each have a laterally extending element 5 be terminated.
• e) deposition of a second layer 25 the electrically and thermally conductive layer 8th , preferably by ALD. This can serve the membrane 3 electrically with the metallization 2m of the substrate 2 connect to.
• f) structuring of the second layer 25 the electrically and thermally conductive layer 8th , This allows a meandering path over the spacer sections 14z and the laterally extending element (s) 5 form. This is preferably as long as possible. In this case, an electrical path from the membrane 3 each having a laterally extending element by the described structures 5 and two spacers 14 walk. The two spacers 14z be down towards the substrate 2 through the laterally extending element 5 completed. As a result, the structures described are electrically switchable in series up to that (continuous) spacer 14d which extends from the top of the second sacrificial layer 10 until metallization 2m extends. Through this continuous spacer 14d So is an electrical connection to the metallization 2m be achieved. The structures described may differ from the membrane 3 seen from meandering from the top of the second sacrificial layer 10 towards the boundary between the first and second sacrificial layers 9 . 10 form. Overall, such a loop-shaped electrical path to metallization 2m be achieved.

The in the 6 illustrated embodiment is relatively similar to that in 5 illustrated embodiment. However, the membrane is located 3 between the first sacrificial layer 9 and the second sacrificial layer 10 so as to be closer to the substrate than a location of maximum distance of the spacer. Furthermore, in the present case, the electrical path of the spacer has only one loop, which in contrast to 5 facing towards the substrate or is open. The final product before etching is in 6 g). A first laterally extending element 5 between the first sacrificial layer 9 and the second sacrificial layer 10 contacts the membrane 3 electric. Around this laterally extending element 5 can be contacted to the outside, a first spacer section 14e be provided, which through the second sacrificial layer 10 to an upper second laterally extending element 5 can penetrate. Another, continuous spacer section 14d is provided which of the outwardly facing surface of the second sacrificial layer 10 So from the top element 5 , up to the metallization 2m of the substrate 2 leads. Between these two spacer sections 14e . 14d could other structures, each consisting of two spacer sections 14z and in each case a further laterally extending element 5 also at the height between the first and second sacrificial layers 9 . 10 could be arranged. Through the second sacrificial layer 10 For example, two more holes 7 be realized, which are then lined with conductive material to further spacer sections 14z to build. In this way, the spacer can be made of a laterally extending elements 5 , such as B. webs, mechanical, electrically and thermally switched into rich spacer cuttings 14 exhibit. In other words, the spacer may be over the spacer portion 14e , which directly over a laterally extending element 5 with the membrane 3 is connected, and the spacer portion 14d which is from the surface of the second sacrificial layer 10 up to the metallization 2m leads, intervening sections 14z again with laterally extending laterally extending elements. In this way, the electrical path and thus the thermal resistance can be increased or increased or the thermal conductance of the electrical path can be reduced.

• a) Falls noch nicht vorhanden kann auf eine Metallisierung 2m eines Substrats 2 eine Opferschicht 9 aufgebracht werden. Diese kann abgeschieden werden. Hierbei kann das Substrat 2, wie auch in den anderen Ausführungsformen eine integrierte Ausleseschaltung 6 (Engl.: Read Out Integrated Circuit, kurz: ROIC) enthalten.
• b) Aufbringung bzw. Abscheidung der Membran 3. Dies kann durch Aufbringen, insbesondere Abscheiden, beispielsweise in Reihenfolge zuerst eines optionalen Schutzoxid 3b und anschließend einer Sensorschicht 3a auf das optionale Schutzoxid 3b geschehen (wie bei 5, außer dass in 6 in dem hier dargestellten Ausführungsbeispiel die Membran 3 auf die erste Opferschicht 9 statt auf die zweite Opferschicht 10 abgeschieden werden kann). Die Sensorschicht 3a kann Halbleitermaterial aufweisen.
• c) Aufbringung (beispielsweise durch Abscheidung) und Strukturierung einer ersten Lage 15 einer elektrisch und thermisch leitfähigen Schicht 8. Somit kann/können aus der elektrischen ersten Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 das/die lateral verlaufenden Elemente 5 gebildet werden, welche zumindest die Membran 3 kontaktieren können und/oder welche die Kehren für die optional vorhandenen jeweils zwei Abstandshalterabschnitte 14z bilden können, welche lediglich die zweite Opferschicht 10 durchdringen sollen. Zum Abscheiden der elektrisch und thermisch leitfähigen Schicht 8 kann ALD verwendet werden.
• d) Aufbringung und/oder Abscheidung der zweiten Opferschicht 10 auf die bisher erzeugte Anordnung.
• e) Strukturierung der zweiten Opferschicht 10. Dies kann Ätzen von Löchern 7 beispielsweise mittels DRIE (vorzugsweise des Bosch-Prozesses) oder mittels lonenätzens umfassen. Dabei kann ein Loch 7 sowohl durch die erste als auch zweite Opferschicht 9, 10 penetrieren und ein weiteres Loch 7 kann lediglich durch die zweite Opferschicht 10 zu dem lateralen Element 5 penetrieren, welches die Membran 3 elektrisch kontaktiert.
• f) Aufbringung, insbesondere Abscheidung, und Strukturierung der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8. Dies kann mittels Lithographie und/oder Ionenätzens geschehen. Somit kann sich ein elektrischer Pfad von der Membran 3 bis zu der Metallisierung 2m ausbilden. Falls mehrere Schleifen über lateral verlaufende Elemente 5 gebildet werden, welche jeweils durch zwei Abstandshalterabschnitte 14z kontaktiert werden, kann der elektrische Pfad folgendermaßen strukturiert werden. Er kann von dem lateral verlaufenden Element 5, welches die Membran 3 kontaktiert, über den damit direkt verbundenen Abstandshalterabschnitt 14e zu dem Abstandshalterabschnitt 14d gehen, welcher durch die erste und zweite Opferschicht 9, 10 zu der Metallisierung 2m des Substrats 2 geht. Dazwischen kann er die einzelnen Strukturen, welche sich aus jeweils einem lateral verlaufenden Element 5 und zwei Abstandshalterabschnitten 14 zusammensetzen, elektrisch in Reihe verbinden. Eine solche Struktur ist in 6g dargestellt. Im Vergleich zu der in 5f dargestellten Ausführungsform ist der Vorteil dieser Ausführungsform in 6f und 6g, dass der Reflektor, welcher sich in 5f beispielsweise unter der Membran 3, d. h. zwischen der Membran 3 und der Metallisierung 2m befindet, entfallen kann. Die Metallisierung 2m unter der Membran 3 der in 6a–6g dargestellten Ausführungsform kann nämlich, als Reflektor für einfallende elektromagnetische Strahlung, insbesondere Licht oder Infrarotlicht, fungieren. Die einzelnen Strukturen, insbesondere die Löcher 7, können ebenfalls in Schritt e) hergestellt werden. Ihre Herstellung kann wie die Herstellung der Strukturen erfolgen, welche in 5a–5f beschrieben wurden.

Processively, such a structure as in the 6a ) -F) are produced:

• a) If not yet available on a metallization 2m a substrate 2 a sacrificial layer 9 be applied. This can be deposited. Here, the substrate 2 as in the other embodiments, an integrated readout circuit 6 (Engl .: Read Out Integrated Circuit, short: ROIC) included.
• b) application or deposition of the membrane 3 , This can be achieved by applying, in particular depositing, for example, first in order of an optional protective oxide 3b and then a sensor layer 3a on the optional protective oxide 3b happen (as in 5 except that in 6 in the embodiment shown here, the membrane 3 on the first sacrificial layer 9 instead of the second sacrificial layer 10 can be separated). The sensor layer 3a may comprise semiconductor material.
• c) application (for example by deposition) and structuring of a first layer 15 an electrically and thermally conductive layer 8th , Thus, can / can from the electrical first layer 15 the electrically and thermally conductive layer 8th the lateral elements 5 are formed, which at least the membrane 3 can contact and / or which are the sweeps for the optional two each spacer sections 14z can form, which only the second sacrificial layer 10 to penetrate. For depositing the electrically and thermally conductive layer 8th ALD can be used.
• d) application and / or deposition of the second sacrificial layer 10 on the previously generated arrangement.
• e) structuring of the second sacrificial layer 10 , This can be etching holes 7 for example by means of DRIE (preferably the Bosch process) or by means of ion etching. This can be a hole 7 through both the first and second sacrificial layers 9 . 10 penetrate and another hole 7 can only through the second sacrificial layer 10 to the lateral element 5 penetrate, which is the membrane 3 electrically contacted.
• f) application, in particular deposition, and structuring of the second layer 25 the electrically and thermally conductive layer 8th , This can be done by means of lithography and / or ion etching. Thus, an electrical path from the membrane 3 up to the metallization 2m form. If multiple loops over laterally extending elements 5 are formed, each by two spacer sections 14z can be contacted, the electrical path can be structured as follows. He can from the laterally extending element 5 which is the membrane 3 contacted, over the directly connected spacer section 14e to the spacer section 14d go through the first and second sacrificial layers 9 . 10 to the metallization 2m of the substrate 2 goes. In between, he can see the individual structures, which each consist of a laterally extending element 5 and two spacer sections 14 put together, electrically connect in series. Such a structure is in 6g shown. Compared to the in 5f illustrated embodiment, the advantage of this embodiment is in 6f and 6g in that the reflector, which is located in 5f for example, under the membrane 3 ie between the membrane 3 and the metallization 2m is, can be omitted. The metallization 2m under the membrane 3 the in 6a - 6g In fact, the embodiment shown can act as a reflector for incident electromagnetic radiation, in particular light or infrared light. The individual structures, especially the holes 7 , can also be prepared in step e). Their preparation can be carried out as the production of structures, which in 5a - 5f have been described.

Regarding the 5 and 6 were thus radiation detectors with a substrate 2 and a membrane 3 described that at least one spacer 14 for holding the membrane 3 spaced from the substrate 2 , for electrical contacting of the membrane 3 with a contact located on the substrate and for thermal insulation of the membrane 3 with respect to the substrate 2 exhibit. The at least one spacer 14 has an electrically and thermally conductive layer 8th on, extending in a section perpendicular to the substrate 2 looped through the at least one spacer 14 extends. The cut surface can run bent, but also be a plane, namely the cutting plane of the figures shown. An electrical path through the at least one spacer 14 in the cut surface, ie the path that cuts through the intersection of the cut surface with the layer 8th results over which the membrane 3 is contacted with a contact or a circuit on or in the substrate is longer than a distance between the substrate 2 and membrane 3 is (as an effect of the loop-shaped formation). The at least one spacer 14 is from a series of laterally objectionable columns or sections 14 formed in pairs at their upper ends or lower ends are joined together to form a loop with this element. At least two columns are in this way via a laterally extending element 5 connected at its upper or lower end. The lateral element 5 For example, it could be between 10% and 50%, or between 20 and 40%, or between 25 and 30% of the membrane-to-membrane distance 3 and substrate 2 from the substrate 2 be located away. Because the laterally extending element in this aspect is relatively close to the substrate 2 can be arranged, the electrical path, which is formed by the individual columns, can be relatively long. Thus, a high thermal resistance of a single column, or by a column, a laterally extending element 5 and another to the lateral running element 5 connected column (including the entire structure) result. It would be possible that a laterally extending element 5 , the two upper or two lower ends of sections or columns of the spacer 14 connects or bridges, at least partially under the membrane 3 extends to form a reflector. It would also be possible that a laterally extending element 5 , the two over or two lower ends of sections or columns of the spacer 14 connects or bridges, equidistant from, or further from, the substrate 2 is spaced as compared to the membrane 3 , The or the laterally extending elements 5 , via which or the electrical path of membrane 3 to substrate 2 through the spacer 14 leads, may or may (in the case of several in the sense of your cumulative resistance) also here, for example, less to a thermal resistance of the spacer 14 contribute as a sum of the thermal resistances of the spacer sections 14z or columns, ie the spacer sections 14z are each of the type as they were already described, which are designed, not just the electrical line between the membrane 3 and substrate 2 to allow, but also to reduce the thermal conductivity as possible. A cross section of the electrically conductive material 8th the individual section or columns, for example, equal to or less than 7 microns ² or less than or equal to 3 microns ² or smaller or equal than 0.8 micron ² is selected to achieve an appropriate thermal resistance behavior, but other values are of course also conceivable ,

For all embodiments described so far is that the laterally extending element 5 can be designed as a bridge. Its length may be at least 2 times its width or more than 5, 10 or 20 times the width. This has the advantage that the thermal resistance of a laterally extending element 5 the smaller the width, and the greater its length, the greater is the larger it is. Thus, if the contact, z. B. by the columns, spacer sections 14z and or spacers 4 . 14 . 14e is formed at opposite ends of the web, the full length of the web or the laterally extending element 5 be used as a thermal resistor.

In 7a - 7y and 8a -D are shown so-called concentric vertical meander nanotube radiation detectors. These differ from the ones in 5a - 5f and 6a - 6g illustrated embodiments, inter alia, characterized in that the individual layers of an electrically and thermally conductive layer 8th may be at least partially arranged one inside the other, so that a loop-shaped, substantially coaxial structure can form, in which the electrical path from the membrane 3 up to the metallization 2m of the substrate 2 can form, in the wall of the spacer 14 itself. The spacer can do this 14 again be formed in a columnar shape, wherein on the wall of the column 45 the individual layers of the electrically and thermally conductive layer 8th are arranged so spaced that, with a small area requirement in the plan view (xy plane) or laterally seen a long electrically conductive path from the membrane 3 up to the metallization 2m of the substrate 2 can be achieved, again considered in the above-mentioned interface perpendicular to the substrate. As the individual layers 15 . 25 . 35 the electrically and thermally conductive layer 8th on the wall of the pillar 45 which the spacer 14 forms, coaxially about the axis z one in the first sacrificial layer 9 etched hole 7 can be arranged, an electrical path can be formed which multiply substantially from the outwardly facing surface (in plan view in the axial direction of the spacer 4 ) of the first sacrificial layer 9 until metallization 2m of the substrate 2 can go. So it can be the distance traveled by the first sacrificial layer 9 is formed, used repeatedly for the electrical path.

• a) Falls erforderlich, Aufbringen einer ersten Opferschicht 9. Dies kann insbesondere durch Abscheidung geschehen. Dabei kann auf ein Substrat 2, insbesondere auf eine Metallisierung 2m eines Substrats 2 kann die erste Opferschicht 9 abgeschieden werden.
• b) Anbringen von Löchern in die erste Opferschicht 9. Dies kann geschehen indem für jeden Abstandshalter 4 bzw. jede Säule ein Loch 7 geätzt wird oder anders erzeugt wird. Beispielsweise geschieht dies mittels eines DRIE-Prozesses (insbesondere des Bosch-Prozesses) oder mittels Ionenätzens. Dabei kann das Loch 7 näherungsweise senkrecht durch die erste Opferschicht 9 ausgebildet sein.
• c) Abscheidung der ersten Lage 15 der elektrisch und thermisch leitfähigen Schicht 8, beispielsweise mittels Atomlagenabscheidung (Engt.: Atomic Layer Deposition, kurz: ALD) und anschließende Strukturierung. Durch die Strukturierung kann erreicht werden dass die abgeschiedene erste Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 im Wesentlichen nur in dem Loch 7 ausgebildet ist. Anschließend kann eine zweite Opferschicht 10 beispielsweise mittels ALD abgeschieden werden. Dies kann über der kompletten Struktur geschehen. Somit kann sowohl die erste Opferschicht 9 als auch die Innenseite der ersten Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 in dem Loch 7 bedeckt sein.
• d) Chemisch mechanisches Polieren. Dabei kann erreicht werden, dass auf der Oberfläche, insbesondere in Richtung der Normalen des Substrats 2 (also in z-Richtung), sich oberhalb der ersten Opferschicht 9 keine zweite Opferschicht 10 oder Überreste der ersten Lage der elektrisch und thermisch leitfähigen Schicht 15 befinden bzw. diese entfernt werden.
• e) Abscheidung einer zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8. Dies kann auf der ersten Opferschicht 9 und innerhalb der zweiten Opferschicht 10 in dem Loch 7 geschehen, so dass sich ein Zwischenraum 45zwa zwischen der ersten Lage 15 und der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 bilden kann.
• f) Strukturierung der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8. Dies kann beispielsweise mittels Lithographie und/oder reaktivem lonenätzen geschehen. Es kann also erreicht werden, dass die zweite Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 im Wesentlichen nur so weit außerhalb des Loches 7 ausgebildet ist, dass die erste Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 elektrisch kontaktiert werden kann.
• g) Abscheidung einer weiteren zweiten Lage 11 der Opferschicht. Dies kann mittels ALD oder Chemical Vapor Deposition (CVD) geschehen. Anschließend kann eine Aufbringung bzw. Abscheidung und Strukturierung einer optionalen Schutzschicht 3a und einer Sensorschicht 3b, welche die Membran 3 bilden können, geschehen. Die Sensorschicht 3b kann Halbleitermaterial umfassen.
• h) Anschließend wird z. B. (Ionen-)Ätzen innerhalb des Abstandshalters 14 vorgenommen werden. Hierdurch wird die weitere zweite Lage 11 der Opferschicht im Lochboden entfernt. Dabei kann auch die zweite elektrisch und thermisch leitfähige Schicht 25 im Lochboden entfernt werden. Die zweite Opferschicht 10 kann jedoch (bei diesem Ätzvorgang) erhalten bleiben. Diese kann später verhindern, dass eine später abgeschiedene dritte Lage 35 der elektrisch und thermisch leitfähigen Schicht 8 die Metallisierung 2m des Substrats 2 elektrisch direkt kontaktieren kann.
• i) Abscheidung einer weiteren zweiten Lage 35 der elektrisch und thermisch leitfähigen Schicht 8. Diese kann die Membran 3, insbesondere die Sensorschicht 3b, elektrisch und thermisch kontaktieren. Diese kann innerhalb der zweiten weiteren Opferschicht 11 in den Topf abgeschieden werden und kann die zweite Lage der elektrisch und thermisch leitfähigen Schicht 25 elektrisch direkt innerhalb des geätzten Loches 7 kontaktieren. Es können nun also sowohl ein Zwischenraum 45zwi zwischen der dritten Lage 35 der elektrisch und thermisch leitfähigen Schicht 8 und der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 als auch ein Zwischenraum 45zwa zwischen der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 und der ersten Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 vorhanden sein. Die einzelnen Lagen 15, 25, 35 der elektrisch und thermisch leitfähigen Schicht 8 können dabei im Wesentlichen zylinderförmig ausgebildet sein. Die zweite und dritte Lage 25, 35 der elektrisch und thermisch leitfähige Schicht 8 können nun durch einen gemeinsamen Topfboden an der der Metallisierung 2m zugewandten Seite des Loches 7 elektrisch miteinander verbunden sein. Auf der gegenüberliegenden Seite, welche nach außen gewandt ist, können die zweite und dritte Lage 25, 35 elektrisch und thermisch leitfähige Schicht 8 elektrisch isoliert, also nicht direkt elektrisch miteinander verbunden, sein. Allerdings können die zweite Lage 25 der elektrisch und thermisch leitfähige Schicht 8 und die erste Lage 15 der elektrisch und thermisch leitfähige Schicht 8 an der nach außen gewandten Seite elektrisch direkt verbunden sein. Die erste Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 und die zweite Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 können aber auf der der Metallisierung 2m zugewandten Seite elektrisch isoliert, also nicht direkt elektrisch miteinander verbunden sein.
• j) Strukturierung der dritten Lage 35 der elektrisch und thermisch leitfähigen Schicht 8. Auf der beschriebenen Anordnung kann lediglich ein schmaler Pfad zwischen der Membran 3 und dem Abstandshalter 14 verbleiben, welcher von elektrischem Strom durchflossen werden kann. Der Pfad sollte deswegen schmal sein, da je schmaler der Pfad ist, der thermische Widerstand gemäß Gl. 1 umso größer ist. Damit kann sich der thermische Leitwert dieses Pfades verringern. Allerdings kann die minimale Breite des Pfads nach unten limitiert sein, da dieser eine mechanische Stabilität aufweisen sollte.

At least two different embodiments can be formed: On the one hand, such a radiation detector 1 with unbroken symmetry (s. 7 ) and on the other hand a radiation detector 1 with broken symmetry (see 8th ). At the in 7 and 8th illustrated embodiments, during manufacture, the inner walls of the electrically and thermally conductive layer 8th with a sacrificial layer 10 . 11 be lined, so that then each of the next layer of the electrically and thermally conductive layer 8th can be deposited. This can in principle be repeated several times. Thus, by repeatedly repeating the deposition of a sacrificial layer 10 . 11 and subsequent deposition of an electrically and thermally conductive layer 8th a loop-shaped structure can be achieved, which in a narrow space in plan view (ie in the xy plane) several times the distance from the metallization 2m to the opposite surface of the first sacrificial layer 9 can cross. This can lengthen the electrical path and thus lead to an increased thermal resistance or a low thermal conductance. In terms of process, the in 7y shown structure are generated in a multi-stage process. This can be done in the steps that are in the 7a to 7 j, and described below:

• a) If necessary, applying a first sacrificial layer 9 , This can be done in particular by deposition. This can be done on a substrate 2 , in particular to a metallization 2m a substrate 2 may be the first sacrificial layer 9 be deposited.
• b) mounting holes in the first sacrificial layer 9 , This can be done by adding each spacer 4 or each column a hole 7 is etched or otherwise generated. For example, this is done by means of a DRIE process (in particular the Bosch process) or by means of ion etching. This can be the hole 7 approximately perpendicular through the first sacrificial layer 9 be educated.
• c) deposition of the first layer 15 the electrically and thermally conductive layer 8th , for example, by atomic layer deposition (Engt .: Atomic Layer Deposition, short: ALD) and subsequent structuring. By structuring can be achieved that the deposited first layer 15 the electrically and thermally conductive layer 8th essentially only in the hole 7 is trained. Subsequently, a second sacrificial layer 10 For example, be deposited by ALD. This can be done over the complete structure. Thus, both the first sacrificial layer 9 as well as the inside of the first layer 15 the electrically and thermally conductive layer 8th in the hole 7 be covered.
• d) chemical mechanical polishing. It can be achieved that on the surface, in particular in the direction of the normal of the substrate 2 (ie in the z-direction), above the first sacrificial layer 9 no second sacrificial layer 10 or remnants of the first layer of the electrically and thermally conductive layer 15 located or removed.
• e) deposition of a second layer 25 the electrically and thermally conductive layer 8th , This may be on the first sacrificial layer 9 and within the second sacrificial layer 10 in the hole 7 done, leaving a gap 45zwa between the first location 15 and the second location 25 the electrically and thermally conductive layer 8th can form.
• f) structuring of the second layer 25 the electrically and thermally conductive layer 8th , This can be done for example by means of lithography and / or reactive ion etching. So it can be achieved that the second layer 25 the electrically and thermally conductive layer 8th essentially only so far out of the hole 7 is formed that the first position 15 the electrically and thermally conductive layer 8th can be contacted electrically.
• g) deposition of another second layer 11 the sacrificial layer. This can be done by ALD or Chemical Vapor Deposition (CVD). Subsequently, an application or deposition and structuring of an optional protective layer 3a and a sensor layer 3b which the membrane 3 can happen. The sensor layer 3b may include semiconductor material.
• h) Subsequently, z. B. (ion) etching within the spacer 14 be made. As a result, the other second layer 11 removed the sacrificial layer in the hole bottom. In this case, the second electrically and thermally conductive layer 25 be removed in the hole bottom. The second sacrificial layer 10 however, can be preserved (during this etching process). This can later prevent a later deposited third layer 35 the electrically and thermally conductive layer 8th the metallization 2m of the substrate 2 can contact directly electrically.
• i) deposition of another second layer 35 the electrically and thermally conductive layer 8th , This can be the membrane 3 , in particular the sensor layer 3b , contact electrical and thermal. This can be within the second further sacrificial layer 11 can be deposited in the pot and can be the second layer of the electrically and thermally conductive layer 25 electrically directly inside the etched hole 7 to contact. So it can be both a gap 45zwi between the third position 35 the electrically and thermally conductive layer 8th and the second location 25 the electrically and thermally conductive layer 8th as well as a gap 45zwa between the second position 25 the electrically and thermally conductive layer 8th and the first location 15 the electrically and thermally conductive layer 8th to be available. The individual layers 15 . 25 . 35 the electrically and thermally conductive layer 8th can be formed substantially cylindrical. The second and third location 25 . 35 the electrically and thermally conductive layer 8th can now through a common bottom of the pot at the metallization 2m facing side of the hole 7 be electrically connected to each other. On the opposite side, which faces outward, the second and third layer can 25 . 35 electrically and thermally conductive layer 8th electrically isolated, so not directly electrically connected to each other, be. However, the second location 25 the electrically and thermally conductive layer 8th and the first location 15 the electrically and thermally conductive layer 8th be electrically connected directly on the side facing outward. The first location 15 the electrically and thermally conductive layer 8th and the second location 25 the electrically and thermally conductive layer 8th but can on the metallization 2m side facing electrically isolated, so not directly electrically connected to each other.
• j) structuring the third situation 35 the electrically and thermally conductive layer 8th , In the described arrangement, only a narrow path between the membrane 3 and the spacer 14 remain, which can be traversed by electric current. The path should therefore be narrow, since the narrower the path, the thermal resistance according to Eq. 1 is larger. This can reduce the thermal conductance of this path. However, the minimum width of the path can be limited downwards, as this should have a mechanical stability.

Finally, this step can also take place before step j) or during step j), an ion etching takes place in the hole bottom. This allows the third layer 35 the electrically and thermally conductive layer 8th be removed in the hole bottom. This serves to ensure that through the hole bottom in the intermediate layer 45zwa between the first location 15 the electrically and thermally conductive layer 8th and the second location 25 the electrically and thermally conductive layer 8th Etching medium can be introduced to the second sacrificial layer 10 to etch away final. The second, second sacrificial layer 11 can be etched away without such a hole, since process technology automatically an opening exists between the other, second layer 35 the electrically and thermally conductive layer 8th and the second location 25 the electrically and thermally conductive layer 8th which, at least after etching away the first sacrificial layer 9 is accessible from the outside.

At the in 7a - 7y illustrated embodiment (see the description in step j)) is thus in the hole bottom 7 a relatively small opening available to the third sacrificial layer 11 etch away. This can in the embodiment, which in the 8a - 8d is shown to be improved.

In 8a - 8d becomes a radiation detector 1 described in a so-called concentric vertical meandering nanotube embodiment with a broken symmetry. In this case, the steps a) to e), the embodiment, which in the 8a - 8d not shown by those already in 7a - 7e described steps.

• a) Strukturierung der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8. Beispielsweise kann dies mittels Lithographie und/oder reaktivem lonenätzen geschehen. In diesem Schritt wird die zylinderförmige Struktur gebrochen. Es wird also nur in einem Teil des Nanotubes bzw. Abstandshalter 45 geätzt. Die Strukturierung kann so von statten gehen, dass die zweite Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 in einem Abschnitt des Abstandshalters 14 weggeätzt werden kann. Somit kann von außen, d. h. von oberhalb der gesamten Anordnung und oberhalb der ersten Opferschicht 9 ein Zugang zur zweiten Opferschicht 10 bestehen zwischen der ersten Lage 15 und der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 zu einem Zwischenraum 45zwa. Die Öffnung zu diesem Zwischenraum 45zwa kann dabei so groß ausgebildet sein, dass Flüssigkeit, insbesondere Ätzmedium, leicht in den beschriebenen Zwischenraum 45zwa zwischen der ersten und der zweiten Lage 15, 25 gelangen kann. Somit kann in einem abschließenden Schritt die zweite Opferschicht 10 leicht durch Ätzen, vorzugsweise chemisches Ätzen, entfernt werden.
• b) Aufbringung, z. B. durch Abscheidung, einer weiteren zweiten Opferschicht 11. Diese kann beispielsweise mittels ALD oder CVD abgeschieden werden. Dabei kann die weitere zweite Lage der Opferschicht 11 sowohl die Innenseite der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 in dem Loch 7, welche Teil des elektrischen Pfades bildet, als auch die obere Seite der bisher beschriebenen Struktur bedecken. Diese umfasst insbesondere die erste Opferschicht 9 und die nach außen gerichtete, d. h. von der Metallisierung 2m entfernten Seite der ersten und zweiten Lagen 15, 25 der elektrisch und thermisch leitfähigen Schicht 8, welche oberhalb der ersten Opferschicht 9 abgeschieden wurde. Des Weiteren wird in diesem Verfahrensschritt die Membran 3 aufgebracht, insbesondere abgeschieden. Diese umfasst eine Sensorschicht 3a, welche auf eine optionale, zuerst abgeschiedenen Schutzschicht 3b abgeschieden werden kann. Die Schutzschicht 3b kann ein Oxid umfassen und die Sensorschicht 3a kann im Wesentlichen aus Halbleitermaterial gefertigt sein.
• c) Ionenätzen der Struktur. Damit wird die weitere zweite Opferschicht 11 im Lochboden 7 entfernt. Hierdurch kann ein Zugang zur zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 im Lochboden 7 geschaffen werden und diese kann kontaktiert werden. Durch Ionenätzen kann selektiv im Lochboden 7 geätzt werden, so dass die weitere zweite Opferschicht 11 nur im Lochboden 7 entfernt wird. Allerdings kann noch die weitere zweite Opferschicht 11 am Innenrand der Zylinder verbleiben. Auf dieser kann nun abgeschieden werden, ohne dass an der Zylinderwand die zweite Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 elektrisch kontaktiert wird (d. h. es kann eine elektrische Isolation bestehen) durch nun abgeschiedene Schichten.
• d) Aufbringen einer dritten Lage 35 der elektrisch und thermisch leitfähigen Schicht 8. Dies erfolgt vorzugsweise durch Abscheidung insbesondere mittels ALD. Anschließend erfolgt eine Strukturierung der dritten Lage 35 der elektrisch und thermisch leitfähigen Schicht 8. Die dritte Lage 35 der elektrisch und thermisch leitfähigen Schicht 8 kann die Membran 3, insbesondere die Sensorschicht 3b der Membran 3, elektrisch und thermisch kontaktieren und mit dem Topfboden verbinden. Wie bereits erwähnt, kann in dem Topfboden eine zweite Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 kontaktiert werden. Somit kann sich ein durchgehender elektrischer Pfad von der Membran 3 bis zur Metallisierung 2m des Substrats 2 ausbilden. Der elektrische Pfad kann dabei in elektrischer Flussrichtung von der Membran 3 über die dritte Lage 35, die zweite Lage 25, die erste Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 bis zur Metallisierung 2m gehen. Im Unterschied zu der in 7 beschriebenen Ausführungsform geht der elektrisch leitfähige Pfad in der Schnittfläche durch die Achse z des Abstandshalters 4. Die Achse z ist in normaler Richtung des Substrats 2 durch das Loch 7 ausgebildet bzw. virtuell vorhanden. In der in 8 beschriebenen Ausführungsform kann sich der elektrische Pfad in der beschriebenen Schnittebene auf beiden Seiten der Achse z ausbilden. In 8d) kann sich der elektrische Pfad in der beschriebenen Schnittfläche durch die Achse z zuerst ausgehend von der Membran 3 durch die der Membran 3 zugewandte Seite der dritten Lage 35 der elektrisch und thermisch leitfähigen Schicht 8 ausbilden. Anschließend kann er in dieser Schnittebene durch den Topfboden in Richtung der zweiten Lage 25 der elektrisch und thermisch leitfähigen Schicht 8 auf der der Membran 3 gegenüberliegenden Seite der Achse z des Loches 7 fließen. Dann kann er sich an der der Metallisierung 2m abgewandten Seite der ersten Opferschicht 9 in die erste Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 ausbilden, und kann sich zum Schluss bis zur Metallisierung 2m ausbilden. Da der elektrisch leitfähige Pfad in dieser Schnittfläche sowohl auf der der Membran 3 zugewandten Seite als auch der Membran 3 abgewandten Seite fließen kann, wird diese Struktur auch als konzentrische Vertikal-Mäander-Nanotube-Strahlungsmeter mit gebrochener Symmetrie bezeichnet. Im Unterschied dazu kann der elektrische Strom in der beschriebenen Schnittfläche in 7 lediglich auf einer Seite fließen, weswegen die in 7 dargestellte Ausführungsform des Strahlungsmeters auch als konzentrisches Vertikal-Mäander-Nanotube-Strahlungsmeter mit ungebrochener Symmetrie bezeichnet wird.

The in the in 8a - 8d illustrated embodiment differs from step f) in the structuring of the second layer 25 the electrically and thermally conductive layer B. The manufacturing process of the embodiment, which in the 8a - 8d is shown, so from the in 7 e) described starting product described. This manufacturing process may include the following additional (manufacturing) steps:

• a) structuring of the second layer 25 the electrically and thermally conductive layer 8th , For example, this can be done by means of lithography and / or reactive ion etching. In this step, the cylindrical structure is broken. It is only in a part of the nanotube or spacers 45 etched. The structuring can be done in such a way that the second layer 25 the electrically and thermally conductive layer 8th in a section of the spacer 14 can be etched away. Thus, from the outside, ie from above the entire arrangement and above the first sacrificial layer 9 an access to the second sacrificial layer 10 exist between the first location 15 and the second location 25 the electrically and thermally conductive layer 8th to a gap 45zwa , The opening to this gap 45zwa can be made so large that the liquid, in particular etching medium, easily in the space described 45zwa between the first and the second position 15 . 25 can get. Thus, in a final step, the second sacrificial layer 10 easily removed by etching, preferably chemical etching.
• b) application, z. B. by deposition, another second sacrificial layer 11 , This can be deposited, for example, by means of ALD or CVD. In this case, the further second layer of the sacrificial layer 11 both the inside of the second layer 25 the electrically and thermally conductive layer 8th in the hole 7 , which forms part of the electrical path, as well as cover the upper side of the structure described so far. This includes in particular the first sacrificial layer 9 and the outward, ie from the metallization 2m distant side of the first and second layers 15 . 25 the electrically and thermally conductive layer 8th which are above the first sacrificial layer 9 was separated. Furthermore, in this process step, the membrane 3 applied, in particular deposited. This includes a sensor layer 3a , which refers to an optional, first deposited protective layer 3b can be deposited. The protective layer 3b may include an oxide and the sensor layer 3a can be made essentially of semiconductor material.
• c) ion etching of the structure. This will be the second sacrificial layer 11 in the hole bottom 7 away. This allows access to the second layer 25 the electrically and thermally conductive layer 8th in the hole bottom 7 be created and this can be contacted. By ion etching can selectively in the hole bottom 7 be etched, leaving the other second sacrificial layer 11 only in the hole bottom 7 Will get removed. However, there may be the second sacrificial layer 11 remain on the inner edge of the cylinder. On this can now be deposited, without that on the cylinder wall, the second layer 25 the electrically and thermally conductive layer 8th electrically contacted (ie, there may be electrical insulation) by now deposited layers.
• d) Apply a third layer 35 the electrically and thermally conductive layer 8th , This is preferably done by deposition, in particular by means of ALD. Subsequently, a structuring of the third layer 35 the electrically and thermally conductive layer 8th , The third location 35 the electrically and thermally conductive layer 8th can the membrane 3 , in particular the sensor layer 3b the membrane 3 , electrically and thermally contact and connect to the bottom of the pot. As already mentioned, in the bottom of the pot, a second layer 25 the electrically and thermally conductive layer 8th be contacted. Thus, a continuous electrical path from the membrane 3 until metallization 2m of the substrate 2 form. The electrical path can be in the electrical flow direction of the membrane 3 about the third location 35 , the second location 25 , the first location 15 the electrically and thermally conductive layer 8th until metallization 2m walk. Unlike the in 7 described embodiment, the electrically conductive path in the sectional area passes through the axis z of the spacer 4 , The axis z is in the normal direction of the substrate 2 through the hole 7 trained or virtually available. In the in 8th described embodiment, the electrical path in the described section plane on both sides of the axis z can form. In 8d ), the electrical path in the described sectional area through the axis z, starting from the membrane 3 through the membrane 3 facing side of the third layer 35 the electrically and thermally conductive layer 8th form. Then he can in this sectional plane through the bottom of the pot in the direction of the second layer 25 the electrically and thermally conductive layer 8th on the membrane 3 opposite side of the axis z of the hole 7 flow. Then he can join the metallization 2m opposite side of the first sacrificial layer 9 in the first location 15 the electrically and thermally conductive layer 8th training, and may end up to metallization 2m form. Because the electrically conductive path in this interface both on the membrane 3 facing side and the membrane 3 This structure is also referred to as concentric vertical meander nanotube radiation meters with refracted symmetry. In contrast, the electric current in the described interface in 7 flow only on one side, which is why the in 7 illustrated embodiment of the radiation meter is also referred to as a concentric vertical meander nanotube radiation meter with unbroken symmetry.

Regarding the 7 and 8th were thus radiation detectors with a substrate 2 and a membrane 3 described that at least one spacer 14 for holding the membrane 3 spaced from the substrate 2 , for electrical contacting of the membrane 3 with a contact located on the substrate and for thermal insulation of the membrane 3 with respect to the substrate 2 exhibit. The at least one spacer 14 has an electrically and thermally conductive layer 8th on, extending in a section perpendicular to the substrate 2 looped through the at least one spacer 14 extends. The cut surface can run bent, but also be a plane, namely the cutting plane of the figures shown. An electrical path through the at least one spacer 14 in the cut surface, ie the path that cuts through the intersection of the cut surface with the layer 8th results over which the membrane 3 is contacted with a contact or a circuit on or in the substrate is longer than a distance between the substrate 2 and membrane 3 is (as an effect of the loop-shaped formation). The at least one spacer 14 is formed as a column, in whose wall the electrically and thermally conductive layer 8th folded is arranged. In the wall of the pillar 45 is the electrically and thermally conductive layer 8th folded is arranged so that in a sectional area which extends longitudinally and through the column, the electrically and thermally conductive layer forms two loops. at 8th forms in a cross section of the column 45 the electrically and thermally conductive layer 8th at least three rings 45r , with spaces in between 45zw between the rings 45r belong to cavities attached to a substrate 2 opposite end are at least partially open, through which opening the Opfermaterialentfernung is facilitated as described.

In the 9a - 9e another embodiment is shown. This illustrated embodiment of the radiation detector is also referred to as a buried nanotube bolometer. This embodiment can be combined in principle with the embodiments described so far. This in 9 e) embodiment shows the finished product. However, the sacrificial shift became 9 not removed yet. The spacer 4 will be an extra distance 62 which extends into the substrate 2 extends into it. The total distance of the spacer 61 can therefore be composed of the distance in the normal direction of the spacer 4 , starting from the upper edge of the substrate 2 to the membrane 3 and the additional distance 62 extending from the top edge of the substrate 2 until metallization 63 which extends in a depression 67 of the substrate 2 located. The upper edge is the edge of the substrate 2 denotes which of the membrane 3 may be facing. Thus, the electrical path at the in 9 extend illustrated embodiment. The thermal resistance can increase with it or the thermal conductivity of the electrical path can decrease.

In principle, one looks like in 9e ) completed construction in cross section in the cut surface as follows. A substrate 2 has at least one recess 67 which is in the substrate 2 in a direction away from the membrane 3 extends. At least the part of the surface of the substrate 2 , which is the membrane 3 is to be facing, can advantageously a metallization 64 have, which can serve, in an advantageous development of incident electromagnetic radiation, in particular light or infrared light, to the membrane 3 reflect back. In a development, the circuit elements of the readout circuit 6 (Engl .: Read Out Integrated Circuit, short: ROIC) on a side of the substrate facing away from the membrane 2 be arranged. In this case, at least one metallization layer 65 for contacting the circuit elements with each other at a height between the membrane 3 facing side of the substrate 2 or the metallization 64 and the bottom of the recess of the substrate 2 arranged. With this metallization layer 65 For example, the circuit elements can be electrically connected. Conversely, the circuit elements 6 , such as B. transistors, resistors and capacitances may be disposed at a level which is lower than the bottom of the recess. The extra distance 62 , is also used for the spacer 4 to extend. This can be used for the spacer 4 in the normal direction a total distance 61 are available, which differ from the electrical contacting of the substrate 2 can extend to the height at which the membrane 3 can be arranged. The entire electrical path from the membrane 3 until the contacting of the substrate 2 can therefore be composed of a first layer 15 an electrically and thermally conductive layer 8th and the spacer 4 , Process technology, such a structure can be produced in a process which z. B. steps a) to e) and will now be described.

• a) Falls noch nicht vorhanden, kann auf ein fertiges Substrat 2, welches bereits eine Kontaktierung für den ROIC 6 aufweist, eine optionale Metallisierung 64 auf der Oberfläche des Substrats 2 aufgebracht, insbesondere abgeschieden, werden. Dies kann mittels ALD oder CVD geschehen. Dies kann zumindest dort geschehen, wo später die Membran 3 darüber angeordnet werden soll. In anderen Worten kann sich nun die Metallisierung 64 auf der der Membran 3 zugewandten Oberfläche des Substrats 2 befinden. Mit der optionalen Metallisierung 64 wird die Absorption von Licht durch die Membran 3 gesteigert. Prinzipiell ist der Strahlungsdetektor aber auch ohne die optionale Metallisierung 64 funktionsfähig.
• b) In diesem Prozessschritt kann (falls noch nicht vorhanden) eine Vertiefung 67 in das Substrat 2 geätzt werden, so dass die Kontaktierung 63 des Substrats 2 zugänglich ist. Dies kann aus der Richtung geschehen, von welcher der Abstandshalter 4 angebracht werden kann. Dieser kann zur Kontaktierung der Metallisierung 63 des Substrats 2 dienen und kann somit zumindest Teil der Verbindung zwischen Membran 3 und ROIC 6 sein.
• c) Auf die bisher beschriebene Struktur wird nun eine erste Opferschicht 9 abgeschieden, welche sowohl die elektrische Kontaktierung aus Metall 67 des Substrats 2 als auch den Reflektor 64 bedeckt.
• d) Nun wird in die Opferschicht 9 ein Loch 7 geätzt. Somit ist zumindest ein Teil der elektrischen Kontaktierungsfläche 63 des Substrats 2 von außen zugänglich. Beispielsweise kann das Ätzen mittels eines DRIE-Prozesses (z. B. eines Boschoder Gyro-Prozesses) oder mittels Ionenätzens geschehen. Dabei sollte das Loch 7 einen Durchmesser aufweisen, so dass ein Abstandshalter 4 in dem Loch 7 aufgebracht, insbesondere abgeschieden, werden kann. Des Weiteren wird in diesem Prozessschritt vor oder nach dem Ätzen des Loches 7 die Membran 3 abgeschieden. In Reihenfolge wird zuerst eine optionale Schutzschicht 3a und anschließend auf die optionale Schutzschicht 3a eine Sensorschicht 3b aufgebracht. Dies kann beispielsweise durch Abscheidung geschehen. Die Sensorschicht 3a kann Halbleitermaterial umfassen.
• e) Zum Abschluss wird nun eine elektrisch und thermisch leitfähige Schicht 8, 15 abgeschieden. Somit ist die Membran 3, insbesondere die Sensorschicht 3b, elektrisch und thermisch mit der metallischen Kontaktierung 63 des Substrats 2 verbunden. Diese elektrisch und thermisch leitfähige Schicht 8, 15 wird nun strukturiert. Dies kann z. B. durch Lithographie oder Ionenätzen geschehen. Somit kann ein elektrischer Pfad, welcher sich von der Membran 3 bis zur Metallisierung 63 erstreckt, vorhanden sein. Da durch die Vertiefung 67 in dem Substrat 2 eine zusätzliche Wegstrecke 62 für die gesamte Wegstrecke 61 hinzukommen kann, kann sich somit der thermische Widerstand des elektrischen Pfades vergrößern bzw. der thermische Leitwert des elektrischen Pfades kann sich verringern.

Starting point can be in a substrate 2 exist on which a metallization 64 and in which an electrical contact for the ROIC 6 is buried.

• a) If not already available, can be applied to a finished substrate 2 , which is already a contact for the ROIC 6 has, an optional metallization 64 on the surface of the substrate 2 applied, in particular deposited. This can be done by ALD or CVD. This can happen at least where later the membrane 3 to be arranged over it. In other words, now the metallization 64 on the membrane 3 facing surface of the substrate 2 are located. With the optional metallization 64 is the absorption of light by the membrane 3 increased. In principle, the radiation detector is also without the optional metallization 64 functioning.
• b) In this process step can (if not already available) a depression 67 in the substrate 2 be etched so that the contacting 63 of the substrate 2 is accessible. This can be done from the direction of which the spacer 4 can be attached. This can be used to contact the metallization 63 of the substrate 2 can serve and thus at least part of the connection between membrane 3 and ROIC 6 be.
• c) The structure described so far is now a first sacrificial layer 9 deposited, which is both the electrical contact of metal 67 of the substrate 2 as well as the reflector 64 covered.
• d) Now get into the sacrificial shift 9 a hole 7 etched. Thus, at least part of the electrical contacting surface 63 of the substrate 2 accessible from outside. For example, the etching may be done by a DRIE process (eg, a Bosch or Gyro process) or by ion etching. This should be the hole 7 have a diameter, so that a spacer 4 in the hole 7 applied, in particular deposited, can be. Furthermore, in this process step, before or after the etching of the hole 7 the membrane 3 deposited. In order, first becomes an optional protective layer 3a and then on the optional protective layer 3a a sensor layer 3b applied. This can be done for example by deposition. The sensor layer 3a may include semiconductor material.
• e) Finally, an electrically and thermally conductive layer 8th . 15 deposited. Thus, the membrane 3 , in particular the sensor layer 3b , electrically and thermally with the metallic contact 63 of the substrate 2 connected. This electrically and thermally conductive layer 8th . 15 will now be structured. This can be z. B. done by lithography or ion etching. Thus, an electrical path extending from the membrane 3 until metallization 63 extends, be present. Because of the depression 67 in the substrate 2 an extra distance 62 for the entire route 61 Thus, the thermal resistance of the electrical path may increase, or the thermal conductance of the electrical path may decrease.

Was thus described in 9 a radiation detector with a substrate 2 again with a depression and with a membrane 3 , wherein the depression in the substrate 2 in a direction away from the membrane 3 extends. The at least one spacer for holding the membrane 3 spaced from the substrate 2 , for electrical contacting of the membrane 3 and for the thermal insulation of the membrane 3 with respect to the substrate 2 , extends into the recess and thus at the same membrane-to-substrate distance longer than it would be without a recess to have a greater thermal resistance. The substratum 2 can be an integrated readout circuit 6 have, which has circuit elements which are on a side facing away from the membrane of the substrate 2 are formed, such as. On the surface or on the surface, protected by a passivation or the like. In this case, a metallization layer 65 for contacting the circuit elements at a height between the membrane 3 facing side of the substrate 2 and the bottom of the recess of the substrate 2 be arranged. The electrical contacting layer 65 connects or wires the circuit elements of the circuit 6 ,

For all embodiments described above, the at least one first spacer 4 . 14 . 14n may have a wall roughness or waviness to complicate phonon transport by surface scattering effects and / or a resultant path lengthening. The wall ripple or wall roughness can be achieved by scallops. The curvature of the amplitude w of the scallops can be greater than 30 nm. In this case, the amplitude of the curvature of the scallops can be designed such that the resulting travel extension is greater than 5% or 10% or 20%. A wall thickness of the at least one spacer 4 . 14 . 14n may be in a range between 0.1 nm and 1 μm or between 1 nm and 0.5 μm or between 10 nm and 100 nm. The respective electrically and thermally conductive layer 8th of the at least one spacer 4 . 14 . 14n may be covered by an etching protection layer. The radiation detector 1 can be a bolometer.

This in 10a - 10d The illustrated embodiment teaches a radiation detector 1 in which a spacer 4 or a first position 15 an electrically and thermally conductive layer 8th a membrane 3 with the metallization 2m of the substrate 2 combines. The substrate 2 again, an integrated readout circuit (Engl .: Read Out Integrated Circuit, short: ROIC) 6 include. In this embodiment, which can be combined in principle with the other embodiments, the spacer has 4 who in 10d shown is Scallops 4s on. These have a preferably microscopic, arcuate configuration. Through this arcuate design of the Scallops 4s at the edge of the spacer 4 For example, phonon transport may be reduced or reduced by surface scattering effects and / or by a resulting path lengthening. The resulting path extension may be more than 5% or 10% or 20% of the direct distance d between ends of the at least one spacer 4 be. A curvature of the scallops can be between 5 and 50 nm or between 10 and 35 nm or between 15 and 25 nm. Alternatively, a roughness or waviness of the at least one spacer 4 or the curvature of the scallops 4s have an amplitude of greater than 30 nm. Thus, phonon transport can be reduced by surface scattering effects and / or by a resulting path lengthening. The scallops can be produced in a smooth sidewall process. Thus, the thermal conductance of the spacer decreases 4 and thus also the thermal conductance of the electrical path from the membrane 3 until metallization 2m of the substrate 2 , The finished radiation meter 1 which is in 10d is shown, shows a substantially cuboid substrate 2 , On this there is a metallization 2m. However, the first sacrificial layer became 9 not yet dismissed, what can be done later. This metallization 2m can be electrically in contact with a membrane 3 which are made up of an optional protective layer 3a and a sensor layer 3b which is arranged above it, can put together. The contact can be made via the mentioned spacer 4 which takes place in the direction of the normal of a surface of the metallization 2m extend kan n and by means of a first location 15 an electrically and thermally conductive layer 8th , which is the first spacer 4 with the membrane 3 , in particular the sensor layer 3b , can connect.

• a) Aufbringen, beispielsweise durch Abscheidung, einer Opferschicht 9 auf die Metallisierung 2m des Substrats 3
• b) Aufbringen, insbesondere Abscheiden, einer Membran 3 auf die Opferschicht 9. Dabei kann auf die beispielsweise plane Oberfläche der Opferschicht 9, zumindest in einem Bereich der beispielsweisen planen Oberfläche, eine optionale Schutzschicht 3a aufgebracht, insbesondere abgeschieden werden. Dies kann vorzugsweise durch ALD oder CVD geschehen. Auf die optionale Schutzschicht 3a wird im Rahmen des Aufbringens der Membran 3 eine Sensorschicht 3b aufgebracht. Dies kann durch Abscheiden geschehen. Insbesondere erfolgt das Aufbringen bzw. Abscheiden auf die optionale Schutzschicht 3b und geschieht vorzugsweise mittels ALD oder CVD. Damit ist die Sensorschicht 3b die Schicht, welche am weitesten von der Metallisierung 2m und dem Substrat 2 entfernt ist. Die optionale Schutzschicht 3b und die Sensorschicht 3a können in diesem Prozessschritt auch strukturiert werden.
• c) In diesem Schritt wird die erste Opferschicht 9 strukturiert. Dies kann durch Ätzens eines Lochs 7 in die erste Opferschicht 9 geschehen. Dies geschieht an der Stelle, an der die Metallisierung 2m elektrisch und mechanisch über eine elektrisch und thermisch leitfähige Schicht 15 bzw. den Abstandshalter 4 kontaktiert werden soll. Beispielsweise kann die Strukturierung der ersten Opferschicht 9 mittels eines DRIE-(insbesondere eines Bosch- oder Gyro-)Prozess erfolgen. Dabei wird der Ätzprozess so abgewandelt, dass sich am Rand des normalerweise im Wesentlichen zylindrischen Loches 7 Scallops bilden. Als Scallops werden vorzugsweise mikroskopische, bogenförmige Wände bezeichnet. Dies dient dazu den Transport der Phononen durch Oberflächen-Streueffekte sowie durch die resultierende Wegverlängerung signifikant zu beeinflussen. Hierdurch kann ein kleiner thermischer Leitwert erreicht werden. Es sind also in dem fertigen Loch 7 in axialer Richtung hintereinander gereihte bogenförmige Ringe des im Wesentlichen zylindrischen Loches 7 vorhanden. Diese können hergestellt werden, indem relativ lange in einem konventionellen Bosch-Ätzprozess chemisch geätzt wird, so dass durch die ungerichtete Ätzrichtung am Rand des Loches 7 sich die vorzugsweise mikroskopischen, bogenförmigen Ringe ausbilden können. Wenn man nun die Ätzdauer eines konventionellen Bosch-Prozesses in den einzelnen Schritten im Vergleich zu dem konventionellen Bosch-Prozess deutlich erhöht und solche Ätzvorgänge mehrfach wiederholt, kann sich ein im Wesentlichen zylindrisches Loch 7 ausbilden, welches an den Wänden sogenannte Scallops 4s aufweisen kann. Alternativ kann ein solches Loch 7, dessen Wände Scallops 4s aufweisen, erzeugt werden, indem ein Bosch-Prozess modifiziert wird, indem zuerst in die Normalenrichtung der Metallisierung 2m durch Ionenätzen geätzt wird. Damit kann man in eine gewisse Tiefe gelangen (ca. ¼ – ¾ der Länge eines Bogens). Nun kann wieder chemisch geätzt werden, um durch das chemische Ätzen die bogenförmige Struktur am Rand des bisher geätzten Loches 7 herstellen zu können. Diese beiden Schritte können nun wiederholt werden, so dass sich ein makroskopisch im Wesentlichen zylindrisches Loch 7 ausbilden kann, welches von der äußeren Oberfläche, welche von der Metallisierung 2m auf der entfernten Seite angeordnet sein kann, bis zur Metallisierung 2m des Substrats 2 erstrecken kann. Da in dieser Variante zusätzlich durch das Ionenätzen sichergestellt werden kann, dass bei einem erneuten Ätzen der alte, d. h. bisher geätzte Bogen, nicht noch einmal chemisch nachgeätzt wird, können klarere Übergänge zwischen den einzelnen Bögen in die Normalenrichtung der Metallisierung 2m erreicht werden.
• d) Im diesem Prozessschritt geschieht das Aufbringen, insbesondere durch Abscheidung, und die Strukturierung der elektrisch und thermisch leitfähigen Schicht 8. Eine erste Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 wird abgeschieden. Diese kann die Membran 3, insbesondere die Sensorschicht 3b der Membran 3, elektrisch und thermisch mit der Metallisierung 2m verbinden. Dabei erstreckt sich die erste Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 zumindest teilweise über die nach außen gewandte Oberfläche der ersten Opferschicht 9 und über die zylindrische Wand des Loches 7. Die Abscheidung kann vorzugsweise mittels ALD geschehen, so dass die Wände des Loches 7 inklusive der Bögen, welche die Scallops 4s bilden, mit dem abgeschiedenen Metall der ersten Lage 15 der elektrisch und thermisch leitfähigen Schicht 8 beschichtet sein können. Somit bildet sich die vorzugsweise mikroskopische Seitenwandrauigkeit aus. Hierdurch wird Phononentransport durch Oberflächenstreueffekte sowie durch die resultierende Wegverlängerung reduziert. Die Lage der elektrisch und thermisch leitfähigen Schicht 8 an der Oberfläche der Opferschicht 9, 10, welche von der Metallisierung 2m entfernt ist, kann so strukturiert werden, dass sich nur ein schmaler elektrischer Pfad ausbildet. Damit kann der thermische Leitwert des elektrischen Pfades von der Sensorschicht 3b bis zum Abstandshalter 4 gemäß Gleichung 4 gering gehalten werden. Durch eine geringe Breite einer elektrisch und thermisch leitfähigen Schicht 8 kann ein kleiner thermischer Leitwert erreicht werden.

Processually, such an embodiment can be made in a multi-step process. The starting point can be in a substrate 2 consist of which as in 10a shown a metallization 2m located. The possible steps will now be explained.

• a) application, for example by deposition, a sacrificial layer 9 on the metallization 2m of the substrate 3
• b) applying, in particular depositing, a membrane 3 on the sacrificial layer 9 , It can on the example planar surface of the sacrificial layer 9 at least in a region of the exemplary planar surface, an optional protective layer 3a applied, in particular deposited. This can preferably be done by ALD or CVD. On the optional protective layer 3a is in the context of applying the membrane 3 a sensor layer 3b applied. This can be done by depositing. In particular, the application or deposition takes place on the optional protective layer 3b and is preferably done by ALD or CVD. This is the sensor layer 3b the layer which farthest from the metallization 2m and the substrate 2 is removed. The optional protective layer 3b and the sensor layer 3a can also be structured in this process step.
• c) In this step becomes the first sacrificial layer 9 structured. This can be done by etching a hole 7 into the first sacrificial layer 9 happen. This happens at the point where the metallization 2m electrical and mechanically via an electrically and thermally conductive layer 15 or the spacer 4 to be contacted. For example, the structuring of the first sacrificial layer 9 by means of a DRIE (in particular a Bosch or gyro) process. In this case, the etching process is modified so that at the edge of the normally substantially cylindrical hole 7 Scallops form. Scallops are preferably called microscopic arcuate walls. This serves to significantly influence the transport of the phonons through surface scattering effects as well as through the resulting path lengthening. As a result, a small thermal conductance can be achieved. So it's in the finished hole 7 arcuate rings of the substantially cylindrical hole arranged one behind the other in the axial direction 7 available. These can be made by chemically etching for a relatively long time in a conventional Bosch etch process, such that the non-directional etch direction at the edge of the hole 7 the preferably microscopic, arcuate rings can form. If the etching time of a conventional Bosch process in the individual steps is significantly increased in comparison to the conventional Bosch process and such etching processes are repeated several times, a substantially cylindrical hole can be formed 7 train, which on the walls so-called Scallops 4s can have. Alternatively, such a hole 7 whose walls are scallops 4s can be generated by modifying a Bosch process by first in the normal direction of the metallization 2m is etched by ion etching. This allows you to reach a certain depth (about ¼ - ¾ of the length of an arch). Now it is again possible to chemically etch, in order to obtain the arc-shaped structure at the edge of the previously etched hole by chemical etching 7 to be able to produce. These two steps can now be repeated, leaving a macroscopically substantially cylindrical hole 7 which may be located from the outer surface, which may be located from the metallization 2m on the far side, to the metallization 2m of the substrate 2 can extend. As can be ensured in this variant in addition by the ion etching, that in a re-etching of the old, ie previously etched arc is not re-etched again chemically, clearer transitions between the individual sheets in the normal direction of the metallization 2m be achieved.
• d) In this process step, the deposition, in particular by deposition, and the structuring of the electrically and thermally conductive layer happens 8th , A first location 15 the electrically and thermally conductive layer 8th is separated. This can be the membrane 3 , in particular the sensor layer 3b the membrane 3 , electrically and thermally with the metallization 2m connect. In this case, the first layer extends 15 the electrically and thermally conductive layer 8th at least partially over the outward-facing surface of the first sacrificial layer 9 and over the cylindrical wall of the hole 7 , The deposition can preferably be done by means of ALD, so that the walls of the hole 7 including the bows that the scallops 4s form, with the deposited metal of the first layer 15 the electrically and thermally conductive layer 8th can be coated. Thus, the preferably microscopic sidewall roughness forms. This reduces phonon transport through surface scattering effects as well as through the resulting path lengthening. The position of the electrically and thermally conductive layer 8th on the surface of the sacrificial layer 9 . 10 which of the metallization 2m is removed, can be structured so that forms only a narrow electrical path. Thus, the thermal conductivity of the electrical path of the sensor layer 3b to the spacer 4 be kept low according to equation 4. By a small width of an electrically and thermally conductive layer 8th a small thermal conductance can be achieved.

The final result is a spacer 4 as he in 10 d is shown. You have Scallops 4s (as shown in the magnification) a length p along the direction between the membrane and the substrate and an amplitude w of the bulges of the scallops measured in the lateral direction. The larger the quotient w / p, the greater the resulting path lengthening of the thermal and electrical path that the conductive material defines in the section surface perpendicular to the substrate. In other words, the higher the w / p, the longer the distance along which the wall of the spacer intersects the cross-sectional area, relative to the direct membrane-to-substrate distance d. According to the invention, the quotient w / p can be chosen and adjusted by implementing, for example, the Bosch process, that the resulting travel extension is greater than 5% or 10% or 20%. In other words, in the electrically conductive layer in the wall of the spacer through the conformal deposition by means of, for example, ALD, the roughness in the wall of the sacrificial layer hole, as caused by, for example, the Bosch process, manifests in a corresponding ripple to that described Path extension leads - the Scallops.

This embodiment, in which by the Scallops 4s a lower thermal conductivity of the spacer 4 can be achieved, can be combined with all other embodiments.

In summary, all aspects, embodiments, developments and features, as far as technically feasible, can be combined with each other. It is Z. B. conceivable that scallops 4s also in the 4a -d, 5a -f, 6a -G, 7a j, 8a -D and 9a E shown embodiments are formed. In particular, it is conceivable that the individual layers of the nested cylinders in the embodiments, which in 7a -J or 8a -D are shown, with scallops 4s be formed. This is at least the first situation 15 the metallization in 7a -J and 8a -D possible. In 4a -D this is both in the first section 4a as well as in the second section 4b of the spacer 4 possible. In the 5a -F and 6a -G is an embodiment with scallops 4s possible with all spacers. At the in 9a In the embodiment shown, it is the spacer 4 also possible to design this with arcuate scallops. Also, a combination with a recessed into the substrate spacers, as in 9a -E shown with the other embodiments of 4a -D to 8a -D and 10a -D possible.

All aspects, embodiments, variants and developments are also possible according to the invention with a membrane 3 which only a sensor layer 3b includes, but no protective layer 3a ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2016/005505 A2 [0017, 0018, 0062]

Cited non-patent literature

• Weiler, Dirk, et al. "Improvements of a digital 25 μm pixel pitch uncooled amorphous silicon TEC-less VGA IRFPA with massively parallel sigma-delta ADC readout. "SPIE Defense, Security, and Sensing. International Society for Optics and Photonics, 2011 [0010]
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• Niklaus, Frank, Christian Vieider, and Henrik Jakobsen. MEMS-based uncooled infrared bolometer arrays: a review. Photonics Asia 2007. International Society for Optics and Photonics, 2007 [0016]

Claims (43)

Radiation detector ( 1 ) - a substrate ( 2 ) and a membrane ( 3 ) - at least one spacer ( 4 ) for holding the membrane ( 3 ) spaced from the substrate ( 2 ), for electrical contacting of the membrane ( 3 ) and for the thermal insulation of the membrane ( 3 ) with respect to the substrate ( 2 ), wherein in one direction between substrate ( 2 ) and membrane ( 3 ) the at least one spacer ( 4 ) into a first section ( 4a ) and a second section ( 4b ) whose length is in each case less than a distance between substrate ( 2 ) and membrane ( 3 ), the first and second sections ( 4a . 4b ) laterally offset from each other and via a laterally extending element ( 5 ), so that the first and second sections ( 4a . 4b ) over the laterally extending element ( 5 ) are electrically connected in series, and wherein the laterally extending element ( 5 ) less than or equal to a thermal resistance of the at least one spacer ( 4 ) contributes as a sum of the thermal resistances of the first and second sections ( 4a . 4b ). Radiation detector ( 1 ) according to claim 1, wherein a cross-section of electrically and thermally conductive material ( 8th ) of the first and second sections ( 4a . 4b ) is less than or equal to 7 μm ² or less than or equal to 3 μm ² or less than or equal to 0.8 μm ² . Radiation detector ( 1 ) according to claim 1 or 2, wherein the laterally extending element ( 5 ) more than 25% of the distance or more than 30% of the distance or more than 45% of the distance from both the substrate ( 2 ) as well as the membrane ( 3 ) or substantially midway between substrate ( 2 ) and membrane ( 3 ), or wherein the laterally extending element ( 5 ) between the membrane ( 3 ) and the substrate ( 2 ) at a distance of between 1 and 2.5 μm from the membrane ( 3 ) and / or spaced from the substrate by more than 2.5 microns. Radiation detector ( 1 ) according to one of the preceding claims, wherein the laterally extending element ( 5 ) as a reflector ( 5a ) is designed for incident electromagnetic radiation. Radiation detector ( 1 ) - a substrate ( 2 ) and a membrane ( 3 ) - at least one spacer ( 14 ) for holding the membrane ( 3 ) spaced from the substrate ( 2 ), for electrical contacting of the membrane ( 3 ) and for the thermal insulation of the membrane ( 3 ) with respect to the substrate ( 2 ), wherein the at least one spacer ( 14 ) an electrically and thermally conductive layer ( 8th ), which in a sectional area perpendicular to the substrate ( 2 ) looped through the at least one spacer ( 14 ), so that an electrical path through the at least one spacer ( 14 ) over which the membrane ( 3 ), is longer than a distance between substrate ( 2 ) and membrane ( 3 ). Radiation detector ( 1 ) according to claim 5, wherein the at least one spacer ( 14 ) is formed of a series of laterally spaced columns connected in pairs at their upper ends or lower ends, at least two columns being connected by a laterally extending element (Fig. 5 ) are connected at its upper or lower end. Radiation detector according to claim 6, wherein the laterally extending element ( 5 ), between 10% and 50% or between 20% and 40% or between 25 and 30% of the distance between membrane ( 3 ) and substrate ( 2 ) from the substrate ( 2 ), or wherein the laterally extending element ( 5 ) between the membrane ( 3 ) and the substrate ( 2 ) at a distance of between 1 and 2.5 μm from the membrane ( 3 ) and / or spaced from the substrate by more than 2.5 microns. Radiation detector ( 1 ) according to one of claims 6 or 7, wherein the laterally extending element ( 5 ) at least partially under the membrane ( 3 ) extends to form a reflector. Radiation detector ( 1 ) according to claim 6, wherein the laterally extending element ( 5 ) equal to or further from the substrate ( 2 ) is spaced as the membrane ( 3 ). Radiation detector ( 1 ) according to one of claims 2 to 4 or 6 to 9, wherein the laterally extending element ( 5 ) is formed as a web whose length is at least 2 times its width or more than 5 or 10 or 20 times the width. Radiation detector ( 1 ) according to claim 5, wherein the at least one spacer ( 14 ) is formed as a column in whose wall the electrically and thermally conductive layer ( 8th ) is arranged folded. Radiation detector ( 1 ) according to claim 11, wherein in the wall of the column ( 45 ) the electrically and thermally conductive layer ( 8th ) is arranged so that in a cut surface which extends longitudinally and through the column, the electrically and thermally conductive layer forms two loops. Radiation detector ( 1 ) according to claim 11, wherein in a cross-section of the column ( 45 ) the electrically and thermally conductive layer ( 8th ) at least three rings ( 45r ) and spaces ( 45zw ) between the rings ( 45r ) belong to cavities formed on a substrate ( 2 ) facing away from the end are at least partially open. Radiation detector ( 1 ), comprising - a substrate ( 2 ) with a depression - a membrane ( 3 ), wherein the depression in the substrate ( 2 ) in a direction away from the membrane ( 3 ) - and at least one spacer ( 4 . 14 ) for holding the membrane ( 3 ) spaced from the substrate ( 2 ), for electrical contacting of the membrane ( 3 ) and for the thermal insulation of the membrane ( 3 ) with respect to the substrate ( 2 ), wherein the at least one spacer ( 4 . 14 ) extends into the recess. A radiation detector according to claim 14, wherein the substrate ( 2 ) an integrated readout circuit ( 6 ), which has circuit elements which, on a side of the substrate facing away from the membrane ( 2 ), wherein a metallization layer ( 65 ) for the electrical connection of the circuit elements with each other at a height between the membrane ( 3 ) facing side of the substrate ( 2 ) and the bottom of the recess of the substrate ( 2 ) is arranged. Radiation detector ( 1 ) according to one of the preceding claims, wherein the at least one spacer ( 4 . 14 . 14n ) has a roughness or waviness with an amplitude greater than 30 nm to reduce phonon transport by surface scattering effects and / or by a resulting path lengthening. Radiation detector ( 1 ) according to one of the preceding claims, wherein a wall thickness of the at least one spacer ( 4 . 14 . 14n ) is in a range between 0.1 nm and 1 μm or between 1 nm and 0.5 μm or between 10 nm and 100 nm. Radiation detector ( 1 ) according to one of the preceding claims, wherein the electrically and thermally conductive layer ( 8th ) of the at least one spacer is covered by an etching protection layer. Radiation detector ( 1 ) according to one of the preceding claims, wherein the radiation detector ( 1 ) is a bolometer. Radiation detector ( 1 ) - a substrate ( 2 ) and a membrane ( 3 ) - at least one spacer ( 14 ) for holding the membrane ( 3 ) spaced from the substrate ( 2 ), for electrical contacting of the membrane ( 3 ) and for the thermal insulation of the membrane ( 3 ) with respect to the substrate ( 2 ), wherein the at least one spacer ( 4 . 14 . 14n ) has a roughness and / or waviness having an amplitude (w) greater than 30 nm to reduce phonon transport by surface scattering effects and / or by the resulting path lengthening. Radiation detector ( 1 ) according to claim 20, wherein the wall roughness or wall waviness is achieved by scallops, A radiation detector according to claim 21, wherein an amplitude of the curvature of the scallop is greater than 30 nm. Radiation detector according to claim 21 or 22, wherein an amplitude of the curvature of the scallop is formed so that the resulting path extension is greater than 5% or 10% or 20%. Method for producing a radiation detector ( 1 ) according to one of claims 1 to 4, wherein the first and second sections ( 4a . 4b ) in each case by means of ALD in openings of a first and / or second sacrificial layer ( 9 . 10 ) getting produced. The method of claim 24, wherein the first and second sections ( 4a . 4b ) by etching a hole ( 7 ) into the first and / or second sacrificial layer ( 9 . 10 ), wherein the etching takes place by means of a DRIE process, wherein a Bosch process and / or Kyro process is used as the DRIE process, so that in the first and / or second sacrificial layer ( 9 . 10 ) Scallops are trained. Method according to claim 24 or 25, comprising the following method steps - structuring of a first sacrificial layer ( 9 ) comprising etching a hole ( 7 ) - depositing a first layer of conductive material to produce a first conductive layer ( 15 ), Structuring the first layer of conductive material to produce a first conductive layer ( 15 ) for generating the laterally extending element ( 5 ), - depositing a second sacrificial layer ( 10 ), - etching a hole ( 7 ) into the second sacrificial layer ( 10 ) for access to the laterally extending element ( 5 ), - deposition of a second layer of conductive material to produce a second conductive layer ( 25 ), - structuring of the second layer of conductive material Method for producing a radiation detector ( 1 ) according to any one of claims 5-13, wherein the electrically and thermally conductive, loop-shaped layer ( 8th ) through the first spacer ( 14 ) is produced by ALD and a sacrificial layer method, wherein a first and at least one second sacrificial layer ( 9 . 10 . 11 ) are deposited, with which the shape of the loop-shaped electrically and thermally conductive layer ( 8th ) is produced. Method for producing a radiation detector ( 1 ) according to claim 27, wherein the first and / or at least one second sacrificial layer ( 9 . 10 ) are structured by etching at least one hole ( 7 ) in the first and / or at least a second sacrificial layer ( 9 . 10 . 11 ), so that a first, second and / or third position ( 15 . 25 . 35 ) of the electrically and thermally conductive layer ( 8th ) can be deposited. Method for producing a radiation detector ( 1 ) according to claim 27 or 28, wherein the first and / or at least one further, second sacrificial layer ( 9 . 10 . 11 ) is deposited by ALD. Method for producing a radiation detector ( 1 ) according to any one of claims 27-29, wherein the first and / or at least one further second sacrificial layer ( 9 . 10 . 11 ) are structured by means of a Bosch process and / or that the deposition of the electrically and thermally conductive layer ( 8th ) by means of Atomic Layer Deposition, Chemical Vapor Deposition and / or Physical Vapor Deposition. Method for producing a radiation detector ( 1 ) according to any one of claims 27-30, wherein for electrically contacting the substrate ( 2 ) the at least one first spacer ( 14 ), which is composed of a series of laterally spaced pillars connected in pairs at their upper ends or lower ends, at least two pillars of the at least one spacer 14 ) via a laterally extending element ( 5 ) are limited downwards during deposition. Method for producing a radiation detector ( 1 ) according to any one of claims 27-31, wherein the membrane ( 3 ) by at least one of the laterally extending elements ( 5 ) is electrically contacted by depositing a first layer of the electrically and thermally conductive layer ( 15 ) on the first sacrificial layer ( 9 ). Method for producing a radiation detector ( 1 ) according to any one of claims 27-32, wherein the at least one spacer ( 14 ) is produced in a multi-stage sacrificial layer method, wherein the at least one spacer ( 14 ) is deposited as a column in the in the multi-stage process on a wall of the column, the electrically and thermally conductive layer ( 8th ) is deposited folded. Method for producing a radiation detector ( 1 ) according to claim 33, comprising - depositing a first sacrificial layer ( 9 ) on the substrate ( 2 ), - etching at least one hole ( 7 ) into the first sacrificial layer ( 9 ), - deposition of a first layer of the electrically and thermally conductive layer ( 15 ) for the production of the first ring ( 45r ) of the first spacer ( 14 ) and subsequent deposition of the second sacrificial layer ( 10 ) - deposition of a second layer of the electrically and thermally conductive layer ( 25 ) for the production of the second ring ( 45r ) of the column ( 45 ) - deposition of a further, second sacrificial layer ( 11 ) - depositing a third layer of electrically and thermally conductive layer ( 35 ) - structuring of the third layer of the electrically and thermally conductive layer ( 35 ). Method for producing a radiation detector ( 1 ) according to claim 34, comprising before, after or during structuring of the third layer of the electrically and thermally conductive layer ( 35 ) removing the third layer of the electrically and thermally conductive layer ( 35 ) takes place in the perforated bottom, so that in said cutting surface on one side of an axis (z) of the first spacer ( 14 ) can form the electrical path. Method for producing a radiation detector ( 1 ) according to one of claims 34 or 35, wherein the removal of the second and / or third layer of the electrically and thermally conductive layer ( 25 . 35 ) happens in the hole bottom by ion etching. Method for producing a radiation detector ( 1 ) according to claim 34, wherein the second layer of the electrically and thermally conductive layer ( 25 ) is selectively structured in an additional step, which occurs immediately after deposition, e.g. Example, by means of lithography and / or reactive ion etching, wherein the cylindrical symmetry of the structure is broken, by only a part of the second layer of the electrically and thermally conductive layer ( 25 ) is removed during structuring. Method for producing a radiation detector ( 1 ) according to one of claims 34-37, wherein after the deposition of the first layer of the electrically and thermally conductive layer ( 15 ) and depositing the second sacrificial layer ( 10 ), but before depositing the second layer of the electrically and thermally conductive layer ( 25 ), a chemical mechanical polishing of the surface of the radiation detector ( 1 ) happens. Method for producing a radiation detector ( 1 ) according to one of claims 25-38, wherein the structuring of the layers of the electrically and thermally conductive layer ( 15 . 25 . 35 ) by means of lithography and / or reactive ion etching. Method for producing a radiation detector ( 1 ) according to any one of claims 25-39, wherein after deposition of the first, second or further, second sacrificial layer ( 9 . 10 . 11 ), preferably in order, protective and / or sensor layer ( 3a . 3b ), which the membrane ( 3 ) are deposited. Method for producing a radiation detector ( 1 ) according to any one of claims 14-23, wherein an electrically and thermally conductive layer ( 8th ), which the at least one spacer ( 14 ) is deposited to or into the well. A method of manufacturing a radiation detector according to any one of claims 20-23, wherein holes ( 7 ) for the separation of spacers ( 14 ) into a sacrificial layer ( 9 ) on the substrate ( 2 ) are etched so that the spacers ( 14 ) after depositing in the holes ( 7 ) have a wall roughness or waviness to reduce phonon transport by surface scattering effects and / or by a resulting path lengthening. Method for producing a radiation detector ( 1 ) according to any of claims 21-42, wherein the at least one spacer ( 14 ) and / or the individual layers of the electrically and thermally conductive layer ( 15 . 25 . 35 ) an etching protection layer is deposited.

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